So many questions for
Why the different screens with the same projector? Confusing - and $1500 for a grey???? Wow.
Go and ask the projector guys this question alone in the under $3000 projector forum. It just seems silly to pay so much for just an average setup... but I could be wrong.
AND GREY FOR A DARK ROOM??? Wow, again. No windows, dark painted walls..... right?
I read all the time that some of the budget screens (+/- $500) do just fine for a $2000 4K projector like that, even my $100 DIY spandex screen is pretty good for most 1080 content. The upgrade per $$$ / better picture is not there (from what I have read) for screen upgrades so a $2000 screen may only be marginally better than say a $700 screen. Better? Yes. How much better is a question for your wallet and piece of mind, Im just saying that I could do a lot with an extra $1300 for just A LITTLE BETTER.
Why 120 inch? I had a 120 inch at a viewing distance of 12 feet and I moved to a 135 inch at 11 feet and my wife and I love it, although sometimes a little busy for 16:9 format but put in a movie and no complaints. Go as big as possible, and AT if possible.
If you do go in wall why not do a AT (acoustic transparent) screen over your speakers? Way way wayyyyy better to have a AT screen no matter what, even with towers (buy three). Can you move the screen out to put all three _____ LCR speakers behind the screen? And three matching vertically speakers is again, better.
The denon 6500 avr is a great choice, just stick with that. Seems to be a good GO TO theater AVR that everyone likes.
YOU WANT FOUR ATMOS!!!!! Just do the four now and not the two now and then two later for another charge. Wire it all now for a one time charge and the four Atmos is a no-brainer.
Control4?? Wow, that is stepping up. If you want to pay someone to come in and set up everything and make it as easy as possible for a four year old to run then go for it. But if you add even a gaming system down the line then you have to hire them to come in and setup a new program for that AT A COST, new 4K player.... yep, new program. I have a harmony elite and it does everything I want easily (including lights) for a reasonable cost, reasonable time and reasonable effort. Start there, you will be just fine.....
Edit - I guess what I am saying is why go a package? If you have the time, energy and want it done right there are so many smart people here to help make your room so much better than.... a package deal.
This is just what I have gathered in my two plus years on this forum, Good luck