Need advice on building a system from a mishmash of components!

The 3 items worth keeping are the 2105 Mac amp the B&W 705 and the Pioneer tuner. These 3 items will keep a solid resale value. Then focus on getting the best sound per dollar. A late model Mac preamp will be a great improvement over both current preamps. Update your sources, can't be specific due to not knowing your financial situation. 

I'd run the Rega Saturn into the Golden Tube preamp and that into the Mac amp. Any of the speakers listed would be just fine try listening and seeing which you prefer. And you have enough gear to build a 2nd system around the Adcom gear and whatever speakers you end up not choosing.

Your room is going to be a big factor in which speakers work best for you.  I'd suggest trying them all with the Mac and Golden Tube preamp, and decide for yourself.

I would keep the Totem and B&W speakers, the Mac amplifier, the tube preamp,  the TT and CD player and tuner. The Maggies may require a different amplifier.

Purchase an outboard phonostage that mates well with the Grado cartridge.

Put a system together then swap out the speakers to get a feel for the sonic characteristics you most enjoy. 

The Adcom gear will likely be used in a secondary system. The 535 amp may serve as a backup. 

Thank you very much for all your time and experienced advice. 

In response to Grisleybutter, some of the items (e.g. Adcom) I have had for many, many years, other items were recently gifted to me and I have not had the opportunity to test them all.) I appreciate your advice on quality - and maybe selling it all for a $1,000 integrated amp.  But first I am going to play, er...  experiment, with what I have - as many of you suggested.  After all, the Mac was recently refurbished and the speakers are like new.  

Yes, GHDPrentice, I agree - I am lucky to have these options.   

Thanks to all of you - your advice was helpful.  Clearly I need to stay up late for some experimenting!  Given the small size of the rooms in my 100+ year old house I think the Maggies are out.  Radio reception is terrible where I live, so the Pioneer is out as well.   Likewise, the cheap sub will be out.   And the Niles, although reported as good quality, will probably be out as well since I won't be using it, and someone else might.

 I am going to research phono--outs for use with the GTA into the Mac to learn how that sounds. (Thanks Russ69, I had forgotten about that option.)  I might have learn about tubes next.  I'm sure the single tube is pretty old.   I have already paired the Adcom with the Mac, so I will see which I like better. Since the B&Ws and Totems are like new, I will keep both sets.  

I'm not sure about the Super Cube 3 sub. More experimenting.  The cheap one is out.

And yes - I will start saving to replace the sources - the Rega and the TT.  They both have a bit of mileage.

Thank you all again!