(1) No, I think that inheriting from both will at worst make MotherClass be checked twice in method resolution.

(2) That should work. The fully qualified name makes export irrelevant. You can always get to a sub that way.

It sounds like your class design still has some weak points. You want some methods of class1 in class2, but you have unspecified reasons not to inherit from class1. Perhaps the common methods should be moved into MotherClass, or else collected into a middle-level one.