We adopted a male GSD when our dog-friendly, playful female husky mix was 10 years old. The GSD boy turned out to be very reactive, and sometimes dog-aggressive. However, our two dogs play well together and are good friends.
I think even DA dogs will do well with friendly, opposite-sex dogs they've known since puppyhood. I believe our older girl has helped our GSD develop better social skills than he would otherwise have had, and she has enjoyed having someone to play with. It has been a good situation for both of them.
Also, since you asked about dominance... our husky mix is normally an independent but submissive dog (except when food is involved!) For the first few months, she dominated the puppy... now he is clearly the dominant dog. We left them to work out those issues on their own, which they did.