Lower intensity by choosing an easier version of an exercise and working 6-8 reps instead. Should give you a bit more hypertrophy, if you're into that plus help strengthen up the tendons and other connective tissue. Strength gain should still be fairly good.
Uhhh, handstand work in the beginning is just the handstand work. Or any other skill work you want to improve on. After that it's free reign whatever you want to do.
Sounds fine. If you want to make it a bit shorter then throw in the last 2-3 exercises from your workout into a short circuit (mix of push/pull/legs) tends to work best. Acts as a brief metabolic workout while still helping you progress with some of the bodyweight work.