That looks pretty darn good! o: I think that style would work perfectly for the rats actually.
My only concern at this point is hairless rats who have no fur at all. xD But otherwise it looks perfect for the rest.
Just so you know, if you want to practice, there is several different types of "varieties" that will be on the site. Some include coat variations, and those are hairless, rex, double rex (rex rat losing their hair), velveteen (like rexes, but with a more wavy style), satin (silky - still not sure how to do this one, make it shiny perhaps?) and harley (which is long haired). Obviously these won't be done all at once. I would probably aim for rex rats to be added after standard, hairless after that and I'm not sure after that.
http://www.ratspacnw.org/varieties.htm Examples are here if you'd like to see.