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

Take your time and try the different combos and compare. Older gear is always somewhat more unpredictable regarding how well they work and resulting sound plus in the end what sound one prefers is always highly subjective to start with.  

I would list them all on ebay and other sites. Use hifishark.com to find what they are worth.

The best value you have the B&W speakers. If you like them, keep them. I personally favor the Totems.

Next is the McIntosh amp. If it’s in great shape, you can sell it for a few grand.

The Rega CD player is highly rated too.

The rest might take a long time to sell and will give you time to play with it.

I don’t see the point of owning more than of anything (but on this site there are people who own 10+ speaker sets or 150+ cartridges but those are clinical cases) unless you have 4 heads but of course you can have 2nd and 3rd systems. My sense is that what you have doesn’t add up to a sweet 1st or 2nd system.

If you don’t want to do a lot of research, just take the easy route, CDs or streaming. You have great speakers (not the subs), a decent CD player and you can get a good integrated amp for a $1000 that’s better than anything you have.

I won't append my first comment. But I reread your post and I am totally confused.

you wrote: "wonderful gifts, purchases and inheritance" 

I assume these three things didn't happen overnight. So you must have a history of building a system or systems and you have plugged (some) these together?

What is your objective? Are you hoarding these items? 

Main System (existing pieces until future upgrades bit by bit)

McIntosh AMP

Adcom Preamp.

***Full Featured: Phono MM and MC; Capacitance choices; Mono; Balance; Tone Controls; and Contour (their version of low volume compensation, boosts bass)

***Two sets of Outputs (allows second system: use Adcom Amp, Golden Preamp with Totem Mites with self powered sub)).

Luxman TT

B&W Speakers

Existing Tuner/CD Player

Sell all the other stuff, including the Tuner if you have no use for it.

Niles speaker Selector: they make good stuff, but for what? You need wires to and from for the main system, not good. Nearby Kitchen Speakers? Better to buy a little compact Bose or other gizmo for the kitchen.

...........................................

Then, bit by bit, upgrade the main system, and use pieces from the main system in the 2nd system if appropriate.

Wish the GTA had phono. 

Just add an outboard phono-pre. Many to choose from, some very good and affordable.