Im going to take a stab at addressing as much as I can.
It sounds like you want to put a TV over another TV (i may have read that wrong). I personally have never preferred that type of setup. I'd much rather be set up side by side.
Most here will die by the projector (me included). I would def wait until you're ready to install to actually buy. That shouldn't stop you from researching which models will fit your throw distance and lighting conditions and know if a new model from the manufacturer is coming soon. That's what I did for my Epson 5040.
I can't say much for TV recommendation. I usually buy the cheapest "4k" tv. I cant personally tell the difference, but I know many here can.
I'll be following your thread to see what you found for blinds. My brother cooked up a combination of insteon, joanne fabric, motorized rollers and channels around the blinds to achieve his black out. It looks great, but he went on a wild goose chase to source it all.
For remotes, look in to iRule if you're a handy techie type and open to buying a bit of extra hardware.