Assume she’s not housebroken, that way if she is then you are pleasantly surprised. I would definitely get her a crate or kennel where she can have her own space. Also, it helps to keep the dogs separated while you aren’t around to supervise. And that helps with potty training. I always try to make time in the evening for each dog to get individual attention. I would put my own dog away in the bedroom for 30-45 minutes and focus on the foster. As for new situations, keep things positive and keeps lots of treats on you at all times. One of our fosters did not like getting in and out of a car but I used treats to lure her into the car and the short car rides were always good because we ended up some place fun like the dog park or out a walk somewhere new.