Rats are cool, I've kept them as pets for a few years now. Kids love them, my neices and nephews get the biggest kick out of them and can't wait to come over and play with them.
They are highly intelligent and adaptable, those are some of the reasons they are chosen for behavior studies. They are very social and interactive, other than the cooking and talking(ok, maybe a couple other things), the movie is pretty close to real rat behavior. One of my rats has me trained rather well, while sitting on my shoulder she will tug on my sleeve for me to raise my arm so she can go and explore.
As far as calling them "cute", that is up to each individual person to decide, you can ask Hzl-eyed-Grl (my ex-sister-in-law) I think I may have sent her a few pics. We have Sphinx rats (hairless) and at first people are weirded out, I think one comment I got was "It looks like someone turned your rat inside out".
On the issue of buying plush: I have a Ty rat that I keep on my desk that I had a hard time finding because they sold out so quickly. I haven't been to the Disney store yet to see what they offer but I may buy if the item look right to me.