Yes. Hamsters from the same litter can ALWAYS mate with each other as long as they're at least 4 weeks old.
Yes.
It is really a personal choice as to whether your doberman has a litter before the dog gets spayed. If you have the puppies a home and they will not be a burden, then let the dog have a litter.
No American Kennal Club says Doberman's do not cope with other dogs.
yes, if you want to
Yes they can... but there is even some chances that they don't....
The Rottweiler is like the Doberman but a lot fatter and sometimes broader. Sometimes they have the same markings as the Doberman.
yes you can
Yes, they will if allowed to.
The same reason you do of course.
litter
It all depends on if you want a litter, because if you let your male cat to mate, you have to be ready. But if you don't want a litter the best thing to do is get your cats fixed.