Congrats on getting a new house! It looks really nice. If I were you, I'd leave the tech out of the living room. I'm a little old fashioned though. Ask your wife what she thinks.
In the downstairs den, I vote no to in-ceiling surrounds. These
NXG Pro 4.1 on wall brackets would be great for your front surrounds. I don't have any experience with dipole speakers, so I can't comment on your intentions there. I have rear surrounds rather than side surrounds, but I like them back there. Again, I'm a little old fashioned.
I'm about to replace my crappy HTIB satellites with a pair of
Fluance bipoles. I'll comment when they're installed and I've played with them a while. But rear surrounds are used so infrequently compared to my front mains, I don't expect any sort of night and day difference.
Since you're on a concrete slab there, you might be better off with a pair of corner-loaded PB-2000.
Edit: According to
this page, if you install dipoles as side surrounds, they need to be directly in line with the couch, not in front or behind. If you're interested in rear surrounds, bipoles would be preferable.
Edit 2: Damn. I actually ordered my Fluance surrounds as refurb because they were cheaper on Friday. If I'd waited and ordered today, I could've gotten them around 20 bucks cheaper, NIB, shipped Prime. I just called Fluance (pronounced FLOO-ahns, which I didn't know till I called and heard it) but it was too late to cancel my order. Moral: If you're in the market for some bipoles and if the Amazon revie
ws are to be trusted, now's the time to order while they're on sale.