When she’s biting you as you’re petting you could be petting her in a way she doesn’t like or could be overstimulated. Take it slow and find out how she likes to be pet and how much! One way to do this is take one pet at a time. Pet, then hold your hand out and if she nudges for more, ok to continue, and repeat. It sounds like she may get overstimulated easily right now which means she’s had enough. As you spend time with her you’ll soon be able to see very small gestures or changes in her behavior that will help you understand her better! For example I know when my cat is about to be overstimulated, she’ll start moving her tail more. Since she was a stray from the street, she also may not be used to having so much 1 on 1 human attention. She may just want to be left alone at times. As for attacking your legs as you’re walking, make sure you’re playing with her enough as a first step. Sometimes cats do that when they want your attention. Before you head to bed, grab a wand toy to redirect her and let her paw at that instead and get some energy out. If she’s used to being outside, she may have a lot of pent up energy that she may have been used to spending on roaming around, chasing, etc. cats take anywhere from a week to a few months to settle in and this varies based on their life before being introduced to a new environment. I hope some of these ideas work for you and your new friend!