I think that you’d have to, otherwise  there’s insufficient information for a sensible response...

Not quite sure

• if there needs to be more Cat6 points 
• of best location for prewiring

First, Sonos is a wireless sound system, so you technically don’t need to wire anything to use it.  However, if you want to use ceiling speakers, than it absolutely makes sense to plan speaker locations and locations to use a Sonos amp.  Where to place them depends on what’s important to you specifically, where you planning on placing furniture, TVs, etc.  I think the forum can help you a bit, but for a home this large, it starts to really make sense to get professional assistance.

That said, for the theatre room, you definitely wanted to wire up speakers there in advance, I would not use Sonos products, except for a Port to connect to the rest of a Sonos system in your home.   Hard to tell the size of the room, but probably a 7.1.2 setup is what I woudl do.  Also, I would lose the double doors for a single door.  You don’t want a ton a light and noise entering the room whenever someone comes in, nor do you want sound to easily travel outside of a room.