She's not stubborn or filled with attitude, she just isn't fully trained. Recall takes a long time to train and has to be done properly.
The same thing with fetch. No breed in her mix is a natural retriever, so it's something that will need to be trained. Inside, she'll do it because inside is a bit boring. Outside, however, is super exciting, so why do this fetch weirdness when she can enjoy the sights and sounds and smells of outside?
As to her resource guarding, that's pretty normal with dogs. Most dog parks forbid toys and treats for that reason. I would personally not allow her to be in that situation in the first place. Set up play dates where she can play with other dogs without toys instead. Someone else may have some ideas on the training aspect, but the more you allow a dog to practice a behavior, the more the behavior gets reinforced. So until you can work on it, don't let it happen in the first place.
The same thing with fetch. No breed in her mix is a natural retriever, so it's something that will need to be trained. Inside, she'll do it because inside is a bit boring. Outside, however, is super exciting, so why do this fetch weirdness when she can enjoy the sights and sounds and smells of outside?
As to her resource guarding, that's pretty normal with dogs. Most dog parks forbid toys and treats for that reason. I would personally not allow her to be in that situation in the first place. Set up play dates where she can play with other dogs without toys instead. Someone else may have some ideas on the training aspect, but the more you allow a dog to practice a behavior, the more the behavior gets reinforced. So until you can work on it, don't let it happen in the first place.