I wouldn't be overly worried about them getting along. We introduced a kitten to our dog who have been king of the castle for many years. He had no choice but to tolerate her and they eventually got on well. Cats are very strong minded and won't take any gof from anyone. When our dog died and we got another we made sure the cat was in the house when the new dog was introduced so he accepted her as part of the package. If anything she now rules the roost and has been known to give him the odd slap if he looks to move her from his bed. Most shelters will advise if a dog gets on with cats