A lot of people here will mention to redirect her to a toy when biting. If the biting is happening while playing, that's pretty normal, but again redirect to a toy that she can bite or even end the play time for a few minutes to let her calm down. We've tried a spray bottle with vinegar and squirting 1 squirt into the mouth when our Ellie would bite. It seemed to help at first, but eventually she just ignored it. Some have used an empty coke can with some pennies in it and they'll shake it when the biting happens.
As for leash walking, once Ellie was used to her collar, we would attach her leash and let her run around the house with the leash attached for 30 minutes or so at a time every night so that she could get used to the weight and it being there. It would just be dragging behind her and we wouldn't hold it. Obviously, do this while you're there to supervise. Then we slowly graduated to walking her across the kitchen/great room, down the hallway, fenced in back yard, etc. until we were comfortable to take her out into the neighborhood.
Both issues will take consistency, repetition, and patience. Hope this helps!