Re: spreading of flavors?
It will be fine. Your rodents should be completely sealed in freezer bags as will be any food in there anyways but if you are at all concerned then simply buy a sterlite or rubbermaid container, put the rats inside there and mark it SNAKE FOOD. Then they won't touch the packages of human food that way. Not that fully frozen stuff should be transferring smell or scent but if it makes you feel better then try it. Nicer too when reaching for a steak you don't accidentally come up with a handful of rat LOL.
Re: spreading of flavors?
It should be fine. As long as everything's all sealed up well.. problems arise when things aren't wrapped right.. freezerburn could also result. We want to avoid:
dad: this steak has a pretty.. unique.. flavor.
you: uh.. can I be excused?
:D