Complete Rinny's arc to be able to go inside; rn you can only buy the living clothes from the NPC if you don't get them from Marin the maid.
Do you mean for Rinny's arc? If so there's a tutorial on it here.
Nope, the idea is that the maid buys it from the shop if you got it from her. If you have female partners disabled, then you'll buy it from the shop, since the maid events won't happen
It's likely! Probably later when his route is more developed~
