I would be a lil worried about them chewing thru the tubs, those tubs have indentions and raised areas in them. If its enough for them to start chewing on, it wont take but about 20 minutes and you will have an empty tub!!!
concrete mixing tubs work best for me
If you wanna use some type of clear tub, it needs to be completely smooth on the inside. As far as TEMPS go, rats breed in the wild all the time without the confort of an A/C.... if you put them in the garage, and it doesnt make you sweat while you are in there... you would probably be ok.
A couple exhaust fans.... one pulling in and one pushing out would prolly be a good idea also. Just an opinion! LOL
Best of Luck to ya