OK @mid-fi-crisis , you've answered the questions, so I'll offer my opinion. I have not heard all of the equipment you have to choose from, so take it with a grain of salt. This is just how I would proceed if I had all of that equipment at my disposal.....
Keep the Prima Luna Integrated and build around it. It is a well regarded piece, it's new, so it should be reliable over the near future and it has remote control (a necessity in my opinion).
Add whatever source components you choose. If you like playing vinyl, and your TT is in good working order, add the TT and your phone stage. Use the Node 2i if you want to stream and connect the Music Hall CD player/DAC if you want to play CDs.
For speakers, I would start with the Magnepans and insure they are set-up in the best position possible. I would listen to them for a while, then I would replace them with the IMFs and insure they are set up properly. I would listen for a while, then choose between those 2 speakers. Of course, you could also try the same with the Magnats and the Infinitys, but I don't think they will be as good as the other 2. I own and use Infinity RS1.5s in my main system and I love them. But they are significantly better than your RSe's.
If neither speaker is "doing it" for you, I would consider demo-ing or buying another pair of speakers and doing some due diligence.
With the remaining equipment, I would either sell some of it to free up funds for upgrades to the main system, or I would set up one vintage system in another room. The winner from your list of vintage equipment is, of course, the Pioneer SX1250. Refurbished SX1250s are selling for $2K-$3K or more, so it would be a nice unit to have, or a valuable item to sell to free up funds. The NAD3020 is a nice unit too, if refurbished, but is not worth much, so I would probably keep it as a backup. I would probably just use the Chromcast Audio as the source for the vintage system, or you could swap in the Music Hall CD, or the Dual TT if you desired.
My system is somewhat similar. I use a modern, powerful integrated amp, with vintage speakers. I have a relatively budget TT setup and I have a modern CD/DAC.
Lastly, I would not want to have that much equipment at my disposal. It's overwhelming (to me). Spend a bit of time, choose your favorites and get rid of the rest. If you sell it, you'll have some extra funds for upgrades (if desired).
BTW, I need to take my own advice and sell off a few pieces I have sitting around.....
Good Luck and Enjoy.........
