Help in putting together my system with used equipment on Audiogon and eBay.

It’s both. You can have a 2 channel preamp running into a 5 channel amp. But you still only have 2 channels of sound. That is assuming analog out and in. If you have digital out, and your preamp has a surround processor, then that would work, depending on the amp. If you were to buy a 5 channel amp, your Pass preamp would only put out a stereo signal in 2 channels of the 5. Generally, for full compatibility both have 5 separate channels. If you want to go the surround route, seriously consider integrated. That’s a whole lot of cabling to deal with, and you could spend half of your budget on cables alone (don’t have to, but could... easily)
Something to consider in your process, the Parasound A21 amp is a serious bang for the buck, and would play nice with your Pass pre. Saves $$$ for speakers. Best Buy has the Magnolia wing, which is their “hi-end” side of things. They should have some good selections to try. They have a very liberal return policy as well if you find something you like in the store. Keep in mind, your room/house will be completely different so take that into account. Ultimately pick what you like, you are the one that will be listening.

My recommendation would be to go and listen to a high end system using vinyl as a source and then using a cd transport or player as a source.  Then figure out what sound you like better and put your money into getting the best sound from that source, rather than hedging your bets and getting a lot of mid-level CD and analog stuff.  I ended up going with vinyl for "serious listening" because it just just sounds better and more pleasing to me.  But, it took some time and it took some money...

I started with a Pass Labs XP15 and a Rega RP6 with the Exact2 Moving Magnet cartridge.  All through really nice CJ tube linestage and amps-- along with Egglestonworks Viginti speakers.  When I put an high quality album on my system I absolutely hated the sound-- classic rock or classic Mozart-- it sucked.  But, it wasn't the electronics or the speakers-- it was the turntable and moving magnet cartridge.

I went to see my friends at Goodwin's High End in Waltham-- just outside of Boston, and they gave me news that I did not want to hear, but was absolutely accurate.  My guy told me "if you want good sound on vinyl, you are going to have to spend a lot more money."  And, he was right.  I dumped the RP6 with the Exact 2 and bought a Rega RP10 with the Apheta 2 MC cartridge, along with a Clear Audio Smart Matrix Pro record cleaning machine.  That made all the difference in the world, but it will eat most of your budget.

There are some Rega RP10 lovers and some RP10 haters on this forum, but I like mine.  Great soundstage, dynamics and plays all kinds of music.  And,  it matches well with the Pass Labs XP15, which I got from Mark at Reno Hifi in Nevada.  Mark is a very likable, knowledgeable and friendly hi fi pro.

I would talk to Mark at Reno HiFi and get a used Pass Labs XP15, which is now around $2,000 and I would get the best turntable you can afford; the Rega RP8 or RP10, especially the 10 is a very nice table, as is the Apheta 2 cartridge.  Others will have their own view, but the RP6 or the P6 does not sound ANYWHERE near as good as the 8 or 10 with the Apheta 2.

When you have that set up, and have spent most of your money, I would look at speakers.  Everybody has their own view, but I like Egglestonworks speakers-- especially the Viginti's.  But, those are a "destination" or reference speaker, meaning those are the last speakers (for my "A" system) that I foresee buying.  The Nico's are smaller, 2 way speakers that are also exceptional, in my view.

Hope this helps in your search.

@imabucfan Do yourself a favor, register for the Florida audio expo, in less than a month, it is free, you just have to drive to Tampa, I went last year and going this one as well, from Miami I go and comeback the same day, last year was their first, this year seems it will twice as big as last, it is a small audio show considering others but you will have the chance to try all sorts of equipment and listen to it.
It will give you a great exposure to what's out there, you just have to wait 25 days or so. I guarantee you it will be worth your wait, then if you want to purchase new or used that's entirely up to you but you will have the reference of what you like.

By the way, after every audio show, even the small ones, the used gear sites will AGon, usaudiomart etc get flooded with used equipment from owners who just purchased new gear so it will be the perfect opportunity for you to grab something of the used market.

Just my 2c, that's what I did when I setup my gear, but I had to flight to Denver at that time.

I am not associated with the expo in any way nor I am in the audio industry as a manufacturer or dealer (yet)
Here is the list of exhibitors

https://floridaaudioexpo.com/exhibitors-2020/
February 7th, free admission

https://www.eventbrite.com/e/florida-audio-expo-tickets-69940837929?utm-medium=discovery&utm-cam...

Have you checked out Kef, ADS or PSB loudspeakers? I know they are old school but they sound good. New KEF is not cheap but they have amazing towers that are full range. I own ADS and if you get the flagship tower model it will give you all the bass and sweet highs you would ever want. Unfortunately some of these brands are getting old and hard to find in good shape. Good luck!