Can't really tell
don't worry about air squats, put some weight on the bar and your form changes completely
most people, me included, can't do a proper air squat without weight
Everyone I think knows the question I'm asking. Am I parallel? On the one hand, I say no. On the other, the angle my shin makes w/my foot is pretty damn sharp, and other people air squatting, squat with a far shallower angle shin/foot angle than me, so the shape of my quads and the relative size of my hip crease might be playing tricks on the eye.
Can't really tell
don't worry about air squats, put some weight on the bar and your form changes completely
most people, me included, can't do a proper air squat without weight
The best view for determining depth is with the camera straight from the side at a height of knee level (and if we're going to be anal about it positioned back to front so it is mid-thigh when the thigh is parallel to the floor but that's a lesser issue) . Then it's just a matter of marking the landmarks and seeing which is higher w/o having any perspective issues to deal with.
Also agree w/ Carnivroar that air squats are harder (for me) to do than squats w/ weight (though i still practice them every w/o as my 1st wu set). Since you were doing work sets at 225 a couple of days ago, i'd think that 115 or 135 would prob be a good weight to check depth without messing up your program or having to worry about the weight.