1. The rarity changing in the Town Hall is a minor visual oopsie that usually results from checking out the town upgrades after looking through the items in the General Store. There is no rarity assigned to Town Upgrades, so feel free to ignore that. It's currently being worked on.

2. Yes (with the exception of the town upgrades, since they don't have any rarity), but we're keeping the mystery to let our players figure it out

3. There are rarities with clothing, but what you might be seeing is simply that you're currently a little unlucky with the random selection, and that will change, eventually.