Is For Rent safe to play if I don't play on a rental lot?

Yes, do play your game! I’ve been avoiding rental lots and tenant/landlord gameplay for now, but I don’t know whether I actually need to or not as I haven’t experienced any bugs myself. I’m just being cautious. But the rest of my game seems to be fine. I’ve visited Tomarang, used plenty of the great stuff from the BB and CAS, used the mould lot challenge, and all with no apparent problems. But do make sure you back up your game just in case.