what speakers to buy

+1 for nycjlee
+1 for John Rutan. He sells both Vandy and Pro Ac and can give you great information. (His Agon ID is 'audioconnection').
Speakers are a personal decision, don't let anyone railroad you. If you can make some time to visit a dealer, I heartily recommend it.
Prior posters have given you a lot of choices, so I hope you can try to audition a few.
BTW, Zu makes some great speakers, at a great price. Since they have a trial period, why not get a pair? All you lose is the shipping should you not like them.
Bob

you cannot listen easily at a dealers but you can 1. take road trips (or add a listening afternoon to a trip to a city), or 2. buy mailorder with a return privilege

for $5k I'd get Maggies - used 3.7i's can be had for $4k 

the question of what speaker to get is first of all what will work in your listening room

all speakers will benefit from being set up away from a corner or back wall (Roy Allison notwithstanding), but it is more important with Magneplanars and electrostatics

1st, you buy speakers (& then use positioning and room treatments to make them sound the best)
2nd, you buy amps to drive the speakers

you will then work to find the best source material for whatever way you are feeding the amps, LP or digital

I usually buy used CDs and rip them onto iTunes - if I really like the album I look to see if there are better recordings or masterings (and even for things recorded in the 1960s there can be better masterings or treatments to remove say wow & flutter on the aged Ampex used to make the original)

Look at ProAc.  Some good deals used.  Most models are two-ways, yet lack nothing in bass.

If you have an open area, you need largish speakers to fill it sound.  I recently purchased Legacy Signature SEs from Dave actually, and definitely love these. However, I also have a soft sport for Focals, and those Utopias are pretty high end. You can't go wrong with either brand IMO. They sound different however, Legacies are warm and engaginng, very high res mind you.  And Focals I always find to be very exciting to listen to, which is also a great thing.

dragonbutx

If you really have to buy without listening I’d be inclined to point you toward Revel speakers. The reason is that they are very well engineered, having been guided by many decades of research using true scientific studies on what type of speaker parameters seem to matter most to our subjective evaluation of sound. (They have used Harmon’s blind testing methods). And the designs have been very competently created to reproduce those results, to produce smooth, neutral sound dispersion in real rooms. And it really works. I recently had been on a big speaker auditioning binge and was surprised to hear even the lower priced Revel speakers - e.g. the $2,000/pair Revel F36’s sounded distinctly more full, more neutral, more refined and controlled top to bottom than some significantly more expensive other brands I had listened to.

Revel Performa3 F208 is around $5,000 and you may find it punches above it’s weight for the reasons above. Here are the Stereophile measurements:

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker-measurements

Now, measurements aren’t going to tell you definitively that you like a speaker. However, if you are really going in blind, speakers by a company that is known to be very technically competent and advanced, and whose speakers measure reliably extremely well, at least helps predict you end up with a well designed speaker that has a great chance at sounding neutral, smooth and well balanced.

Of course, the best bang for the buck will likely be used speakers. But even then, you may get an expensive speaker at 1/2 price used, that wasn’t particularly well designed and even a cheaper well designed speaker (e.g Revel or others) will beat it.

One final note, if you are in fact sort of new to putting together a higher end system: I would caution you about taking advice to spend a significant portion of your budget on audiophile cables. I’d suggest buying cables known to be well engineered (and for which measurements are supplied vs "wow" sounding subjective descriptions), for instance some Belden Cable from Blue Jeans cable or similar outlet.
Those will feed your speakers all the signal they require, you can start there, put your budget into things that will make the biggest difference - e.g. speakers - and later on when you suddenly become flush with cash and get the itch, you can experiment with the expensive cables.
(Most audiophiles, unfortunately, use protocols for determining sonic differences that are little different from those used to "show" that every alternative medicine, new age therapy, astrology etc are all effective. Which should give you a clue as to how much stock to put in to many of the claims you’ll encounter for high priced cables. My pal has a system with $50,000 in high end cables. My system with simple, relatively low priced Belden cables sounds much better - he would agree - because I put the money where it would matter - speakers, room treatment).

revels aren't very directional and work very well in open configurations

I think a general strategy here would be to make smart used buys keeping resale value in mind. Essentially create for yourself an extended auditioning program by buying right and reselling and moving on if the speakers don't work for your room or electronics. I know it's not as easy with speakers but short of traveling to retail shops or audio shows you don't have many other options. Speakers are a very personal choice more than any other component.

Second the used Wilson concept. Also think very highly of Revel.

The "don't buy without listening" is not a problem with the new patented line of Tekton speakers. The owner of Tekton Design Eric Alexander allows a 60 day listening period. 
I personally purchased a pair of Tekton Impacts believing I would be returning. The first listening session began at 6:30 pm and finally ended at 4:30 the following morning. They replaced a pair of Magnepan3.5r speakers I had loved for 20 years. I paid $1800.00 for the Impact's.
Check out the Tekton Double Impact thread here. Several of the posts reveal the Tektons replacing $30,000 per pair speakers with this $3000 pair.
I have no affiliation with Tekton. I just consider myself very fortunate for finding what I consider the best speakers I have ever heard.
I think you would be shocked at the capabilities.
Listen Intently.

+1 Inna. Don't hesitate - those Focals are a great place to start and would hold their value.

Vandys are too low without enough bass for such a big room, also they are not known for loud volum or rock.

The focals mentioned above are great for a large room and as they are a tad bright will compliment the Rogues

Another good choice Psb T3 big tight bass great with Rogue.

I would hop on those Focals.

Troy 
Audio Doctor Nj

I’m not much of a Wilson fan myself, but used Wilsons are a great buy, IMO. Wilson is constantly coming out with Mark 2, Mark 3 and other versions, causing the owners to dump their speakers at very good prices. Personally, If I had the room, I would go for a pair of Sophias. You can even get them used from Wilson dealers, certified and in mint condition at very reasonable prices. There's 2 pairs of Sophia 2s up right now at $5500 from dealers.  
I think that's a great buy myself.  I heard the Sophia's at one of the shows with Lamm tube gear and they sounded very good.  For me, I much prefer the smaller Wilsons to the larger ones, but that's me. 

I’m on the same page with Troy. What kind of music do you play and how loud? Also, what city do you live in?

Being a Vandy fan....I would recommend something from the Vandersteen line. The TREO CT would sound awesome with the Rogues (I have TREO CTs). Btw, I would give Johnny Rutan at Audio Connection a call, he carries both Rogue and Vandersteens and will give you some good advise. Personally and in my opinion, in a high ceiling and open space, one of the best speakers I’ve heard was the Devore Orangutan O/96, power by a Leben CS600 tube integrated amp. Very musical (both highs and lows) and if jazz is your thing, give it some juice...close your eyes and you’ll feel like you’re right there inside the club. A bit out of your budget even used but they maybe worth saving up for. Good luck!

You may want to check into something in the Golden Ear Technology Triton Tower line. https://www.goldenear.com/products/triton-series

I like speakers with big sound and also those with as few drivers as possible. In addition, I think, and someone will corect me if I am wrong or not quite right, that Danish speakers are designed with solid state electronics in mind.
If you do eventually decide to get Focals, you might want later to upgrade your Rogue to VAC, Allnic or somethign else to take the sound to the next level. Cabling will be important too, isn't it always? Purist Neptune fluid cables should be great. Or Echole. I am sure some others would work fine as well if that's too expensive, something like Fusion Audio Magic line.

You must remember that your open plan layout requires bigger speakers with alot of bass output. Here are a few things to consider:

1: Is the room very lively, if you talk loudly do you hear revereration of echo of your voice in the space, if it is very reflective then speakers which tend to sound bright might be a bad thing.

2: What kinds of music do you like to play? 

3: How loud do you play?

The Alto Utopias that Inna mentioned are quite excellent they have a big sound and will work well with the Rouges which tend to sound a bit rolled off and lack a bit of bass control but the JM Labs also tend to be a bit on the Hard side, so the combination should be excellent.

How many squre feet is the room including ceilings? 

Leacy speakers are a steal they sound like $15k speakers yet are brand new at $7k and they have a smooth sound in the top, and a lot of bass. 

Older Kef 207.2 are awesome. 

The Dali Helicon 800 you mentioned are terrific as well.

Troy
Audio Doctor NJ

You cannot audition speakers but, with great caution, you can listen to some systems on youtube. There is one company that recorded many systems at shows. Their recording quality is average at best but it is at least usually consistent. If you have good enough headphones you can hear the difference. I will not tell you what I liked most because it is far outside your range, even the least expensive models. This might help you focus on, say, a dozen of speakers. For $5k-$6k used there are so many good and very different speakers.

I would consider these too, especially with tube electronics.
https://www.audiogon.com/listings/full-range-jm-labs-utopia-alto-be-2017-09-24-speakers