How would they have prevented it. or even known about it if the odor wasn't there until day 2? A previous guest could have left a patio door open, and a mouse could've gotten in...crawled into the pump access area, and between the tub and back wall...there'd have been no way to tell it was there until it started to smell. And that doesn't just happen with jetted tubs...ALL tubs have an area between the tub and wall that an animal can get into through the plumbing access panels.
As far as the appliances, it is not reasonable to expect a timeshare engineer to check each appliance, USB port,, or electrical outlet between guests. They rely on guests to report the problems.
Knowing the animal removal would require pulling the tub, offering the relocation was the best option for all involved. Nothing is perfect, things happen. All resorts have rooms go do=wn unexpectedly. Pipes burst or leak, appliances die, water heaters die, animals squeeze into places they shouldn't be, A/Cs die or leak. The OP got a lemon of a room, often the best option is to just relocate...it isn't an unusual thing. It can happen when you travel, whether it is a Four Seasons or Disney or Motel 6.