Finalized the A/V finally. Last piece was the surrounds. Here's what I ended up with:
Motorized 84" tab-tensioned screen -
http://www.elitescreens.com/front/front/productdetail/product/60 - chose a low gain as the projector throws a lot of light
Panasonic LCD Projector -
http://www.projectorcentral.com/Panasonic-PT-AX200U.htm This is a hand-me-down from my pop. 6-8 yrs old, but lightly used. 720P, will work well for my needs. Will ceiling mount, this projector has plenty of lens-shift to bring it down.
Denon X1200W Receiver -
https://usa.denon.com/us/product/hometheater/receivers/avrx1200w . More than enough power for my needs, 4K capable, Atmos-capable, 6 HDMI inputs. I got a scratch-and-dent from Crutchfield - this thing was brand new. Excited to set it up
KEF Q300 front speakers (bookshelf) -
http://us.kef.com/q300 These are highly rated bookshelves. I wanted bookshelf to get the speakers up and out of the way of the kids. Will mount to the wall (bought a pivoting bracket).
Definitive Technology Mythos Gem (surrounds) -
https://www.definitivetechnology.com/products/mythos-gem I needed a very narrow (<6") speaker which significantly narrowed (pun intended) my options. DefTech has a great reputation, so these should do well
SVS SB-1000 subwoofer (12" sealed) -
https://www.svsound.com/products/sb-1000 I knew I wanted to go SVS, and found a guy a few towns over who bought this, used it once, and ended up preferring his tower speakers (music use only). Sold it to me half-price.
Overall will run a 4.1 system (phantom center). I ran a wire to add a center (below screen) later, but for now don't want the kids to mess with it. The nature of the room doesn't really support 7.1 or Atmos, so didn't run any other wires.
Ended up doing a 'built in' rack (this one)
https://www.amazon.com/Navepoint-Wallmount-Cabinet-Enclosure-16-Inches/dp/B00JZVUDLQ/ so will rack-mount everything.
Only thing left is to install it all and buy a Harmony remote...