Wow, $7 is the lowest rate I have ever heard of.
In the Northeast, $25-$35 is more common.
At that price (or actually at any price) I would ask alot of questions. It sounds like you already have asked alot. Just try an internet search for how to choose a doggy daycare, and you will find checklists to make sure it is a high quality safe daycare with good cleanliness and constant supervision. It sounds like a good place so far since there is a behaviorist and separate small dogs area.
Good luck! London goes to daycare everyday, and she has grown into a lovely young lady because of it.