Should I Keep This Dog? She Has So Many Issues!?

We rescued a dog over 3 weeks ago from a shelter. Not much was known about her. Shes 3, probably a cockapoo and was either a stray or neglected but probably did live inside at one point (only had one accident and has held it for 10 hours before!). She doesn’t shed (YAY!!!) she’s incredibly loving (to me and my husband), cute and has funny quircks.. but she also has some “baggage” and behavior issues.
1. She’s very protective over her toys,treats, and sometimes her space – has bitten kids lightly.. my 6 year old doesn’t like her that much and is afraid of her.. he’s dramatic but still..I want him to like the dog!
2. She doesn’t come when you call.. she hears you, see’s you, but she chooses not to come. She’s not a big pleaser. More like a cat.
3. She just started humping our pillows AND humped me yesterday! I flipped! She was spayed 3 weeks ago!! It totally grosses me out! Guess she wants to be top dog. No no!
4. Not the easiest to train. Got past “sit” but sometimes she doesn’t