In-Ceiling Help

I’m doing a remodel of my house - a small rancher. To open things up, I took out a wall between the family room and kitchen and the family room looks something like:

----------------------------
| .............tv................|
W
W
W
W
| ............sofa
D
|
----------------------------

W = window, D = door, | & - = wall

Because of the missing wall, window placement, and size of the room, I am considering In-ceiling speakers. Is it possible to have decent sound from a setup like this? I don’t need audiophile quality, but still want to feel immersed and don’t want to feel like the movie is happening above me. Speaker advice please! So far, I am looking at

martinlogan ml-67s ~ $150 each.
martinlogan helos-12 ~$275 each (cheapest I could find on these)
polk LC80 ~ $275 each (refirb)

As far as electronics, I need a 4k UHD friendly receiver of some sort to pair with these. Pricewise, something that makes sense with speakers in this range.

I appreciate any advice you can offer.

P.S. I have ad lower end hi-fi stereo setups in the past (eg Apogees). I see theater largely as a different experience. If using this solely for movies, will going to a HT system in this price range be a serious downgrade?

Thanks!