ahhk, I have a similar issue, my knees buckle inwards so to speak.
Is Leesh flat footedd? (that was hard to ask without it sounding like talking about her as if she isnt around) or even walk like a duck? (feet facing out instead of straight).
Trent (PTC Sydney) noticed this on me, which I have known about and never gave it a second thought, need to work on walking properly and also recommended I buy some squatting shoes. As well as a lot of mobility exercises.
Shoes made and instant difference with my squat, so maybe look at what she/you are squatting in as well as mobility and technique.
In regards to pull ups, is it just that you don't feel it in the back or can't do them? Maybe try some assisted chins at a difficult level and really focus in on your back?