Just to bring something new to the Roxaane and Mona explanation....

I think they just did the same thing they did with Max that they did with Roxanne.

You gotta remember that Max's original form was WAY different. He was Goof Jr. and didn't look anything like his dad. However, when Goof Troop came around, they changed his look completely.

They could have done the same thing with Roxaane.


That's just what I think, a second guess is that they grew apart because there is obviously a good time change between the two movies.