Need advice on dominant dog?

As already stated, it's hard to say without seeing the dog, I would say go see a trainer, dominance over another dog is hard to say. With your smaller male, he is smaller then her so she may think she is more dominant, which is sometimes the case. The water bowl sounds like she is guarding. If she's aggressive towards other dogs, this may be an aggression issue, which trainer would help you with, but you could also continue to tell her no when she does these things and use positive reinforcements. So say "No, share" for example when she is with the water bowl and when she backs off praise her a lot. Some dogs get this way when they aren't getting enough exercise too. I'm not sure if this is the case or not. A trainer is your best bet though. I wish you luck :)