When you talk about trying to avoid knee popping, do you just try and keep the knee at a consistent/gradual bend during the pass through?

Almost. Don’t let it go too far from straight to bend (or vice versa) over 1 frame.

This means controlling the spacing on what ever part is causing the pop.  (Could be the distance the foot is moving from the hips or it could be the raising of the heel or many other things)

So I wouldn’t keep it a consistent bend, it just needs to ease in/out of any big changes.

Don’t worry if you struggle at first, you are picking it up really quickly so it won’t take long before you know how to handle it.