Curiosity101
Is now at University! :D
its ok we might be selling her anyway :'(
Aww why?
If it's her behaviour that is the issue then that is often easily (well... easily but it takes along time) fixed. You just need to get in touch with some dog trainers and find one that you feel you could work with to help improve her.
To me it does just sound like possessive behaviour which can become dangerous/agressive behaviour over time. But is quite straight forward to sort out.
And the male dog agression could partially be down to the fact she is unspayed, and partly due to not being properly socialised as a pup, again this is normally something that can be fixed by going to regular socialisation/puppy classes
If you and your family love her and have the time/money to give her the training she needs then definitely do it!
Oh and well done on teaching her tricks, it shows she's clearly capable of learning. But IMO (for future reference though remembering I am not a dog trainer), I would never train tricks before important things such as the 'leave' command, socialisation from a young age and the 'return/heel' command.
The 'leave' command is an invaluable tool for young dogs. You can quickly teach them what they can and can't do and avoid problems from a distance as opposed to having to leap across the room to remove whatever object is about to go into the dogs mouth! lol.
Another useful one is crate training. Once trained you can follow on to teach the command of 'bed'. And easily and quickly remove the dog from a situation without needing to use force and the crate is seen as a positive place for the dog so they normally are happy to go when instructed.