If it's a product team, you can easily have a company with 4-5 teams (design, development, marketing/sales, support, content) so it's not to uncommon to have a team grow to that size. And this size is still manageable, if they are not all doing the same.
For me 30 is the max, I prefer it smaller, too.
> 3 person office
For me that's the ideal tag team: a junior, a medior and a senior working hand in hand is great. In general I find my to be the most agile in teams of three. 3 opinions are a choice, and you can quickly find input if you don't have to stand up to move.
If I'm in the office I want to use that opportunity to be in close contact.
> The wall covering the door
You can peak through the window left and right of the door to see everyone in the room.
> Bathroom stalls
Good point, I'll just update the design (similar to the shower)
> Library
Yes, you could be right.