Questions on the Brittany Spaniel?

Your dog needs a solid recall before it can be off leash trained. Brittanys are usually pretty reliable dogs. I have seen some on our local beach do fine. And sibes can be taught to recall, but it takes extensive effort, and isn't practical for most people. A brittany is easier to train. Honestly, most dogs aren't too same sex aggressive, and brittanys are a pretty dog friendly breed, but introduce the dogs correctly. And that could be sufficient, but your brittany probably won't want to play in the yard alone, or wander, they only want to be with you. It could count as exercise if it had another dog to play with.