Ideal Setup for Very Large Open Living Room

Where will the TV be place? Is the intention that the entire open space have good/great audio for TV watching or primarily the living room? About what percentage of time are you watching TV vs listening to music?

I don't think the Beam is the way to go, probably a playbar, but what other speakers depends on what you r needs are.

TV will be above the fireplace on the far right. Sofa roughly in the middle of the room maybe 10-12ft from fireplace. The rears would go at the very far left in the corners. TV is 75%, Music is 25%. Mostly good/great audio for the living room not necessarily the entire space. Maybe Play:3's instead of Play:1's to help as well?

Ok, so at the front, I definitely would not go with a Beam. I'd go with a playbar. If this is new construction, where you can get behind the walls, then I'd seriously look at possibly using a Sonos amp with prewired cable to the left and right speakers. It will give you more power to cover the whole room than the playbar would, though it's fine for where your sofa is located.

For the surrounds, I don't know that I'd want to put them all the way on the back wall. It will work, but when used as surround sound for TV, it's going to overpower the front speakers for people in the dining room. I have a similar setup where my kitchen is behind the living room, and the speakers are on the kitchen back wall. Play:3s are a good idea with that setup (I use them too) particularly when it comes to full music playback.

If you can, I'd consider putting surround speakers mid room, behind couch. It looks like electrical could be an issue there. Ceiling speakers might be nice (with Sonos amp), but not sure on the sloped ceiling. If there is floor power outlet in the middle of the room, that would be ideal. You could place sonos ones on stands right behind the couch. If you do that, then you can have another pair of play:1s/sonos ones in the dinning room. You wouldn't turn those on for tv, but it will be nice for music.

For the kitchen, I'd use a pair of play:1s/sonos ones, for music. Again though, if this is pre-construction, ceiling speakers (with amp) would be a nice choice. you won't have to figure out where to put speakers on the counter or mounted on the wall.

One good thing with Sonos is you add speakers one or two at a time and build your system. You can try surround in the back at first, then move them to the mid-room to see what works best for your need, Add kitchen speakers if needed later.