Interesting about Andrews. Don’t even want to ask how you got that info.
Are you advising the other dorms you did mention–Perkins, Hope, Littlefield–are first-year dorms? Dunno about that. So not following you here.
OP: The standard configuration at Brown is communal bathrooms. That includes all freshman dorms. Exceptions are some upperclass dorms that have suite or apartment configurations, such as Minden and Barbour for example. There are probably a few others.
If you see a dorm described as containing singles and doubles, primarily (as opposed to suites or apartments) you can be pretty well-assured there are communal, not individual bathrooms. Kinda makes sense, right?
How many people are using the bathrooms at any given time…I have no clue.