Suggestions for my floorplan

If Budget is not an issue and you want good to best ‘quality’ experience I’d recommend....

Breakfast Room/Kitchen: pair of Play1s and a sub in the breakfast room.... which can be grouped with the a pair of sonos Ones in the Kitchen. I have a very similar shape/config and have this exact setup and it works v well. Not overkill at all and I sounds so much better and fuller than the previous setup I had which was a pair of Play 3s shared between the same space. I went Play 3 pair. Then added the Ones in the kitchen. Then added the Sub. Then replaced the 3s with 1s to slim back down (only for aesthetic reasons). If you’re planning a TV area as you mention, consider a beam here also.

Family Room: already covered with your 5.1 plans. This will be v good but not ‘best’ for movies as high res codecs not supported. But overall still great and awesome for music. Given the size - assuming you can/want to ‘play loud’ with no consequence from neighbours etc, I’d consider play 3s or even Play 5s as rears to fill the room in music mode from the playbar and place the sub near the playbar to balance our the bass distribution. My main ‘lounge’ is smaller, so Play 5s were overkill - but I tested it and in a space that size I’d be doing it.

Living Room: Toss Up between a pair of 1s and a Sub and a pair of 5s. Depends how much you want/like the stereo separation and ‘full’ sound. Frankly I was rather disappointed with ‘single speaker’ performance from Sonos. If I had not gone down the pairs and Sub route I’d probably have not bought any more. Paired and with a Sub is a whole other level and more on a par with ‘proper’ (aka, more traditional amp and bookshelf/floor stander level). But if your point if reference is a BT Bose then this is not an issue.

If you want the full whole house experience consider dotting a few 1/Ones around the Foyer and Stairwell.

If you spend a lot of time tinkering in the garage then start off with a single unit and keep adding until you’re happy with the sound. Given the size of the space, if I spent a lot of time in there 4xp1 would not be wasted. Mine is half that size and I have 2xOne.

I’d also recommend getting a speaker or two with floor stands, then you can easily move around once you have the ‘basics’ covered and figure out what is optimal for your needs. Saves buying unnecessarily.

Good luck and enjoy!

Just to add another point of view.... You don't have to go all out to get great sound. Assuming your tv is on the left wall near the fireplace, then you could get a pair of play 3s in the kitchen for surround sound. You can place one on top of the fridge, and one at the end of the counter. Some may say you should put your surrounds on the island, but I don't think it makes that much of a difference for surround, and it includes the kitchen to the plan. For music in full mood, you'll get full stereo out of those speakers. You could maybe go with the smaller Play:1s or Sonos One, but I'd go for a little more since this is your main listening area. I wouldn't worry about the breakfast room, it will be covered already.

For the Office, I'd stick with a pair of 1s or Ones. I'm guessing you need the bass thumping much in your office, and you aren't going to be blasting music at high volumes there, particularly since it's fairly open to the main living space.

Same plan for the sitting area, just a pair. Although I probably would look to put speakers in your bedroom before this room. If you add a tv and beam later on, you may not want anything else.

Garage? Depends on how much you're in there. Don't start throwing money at spaces you don't use much. Same goes for any backyard setup.