I am not going to answer all of this because a lot of it is explained by just watching the videos.
If you watch the videos and mimic what I'm doing, and follow the inhale/exhale instructions, you should be fine. A lot of these questions are redundant. You are overcomplicating the exercises greatly.
Form 1, the hands can touch on the way down or not. It really doesn't matter. You inhale as you begin to raise the arms up, and exhale as you bring them down. You do not bend the knees at all in coordination with hand movements. Keep the knees slightly bent and stick your hips out to straighten the small of your back. This is basically the Wu Qi (Wu Chi) stance. Keep your legs locked in this position and stable the whole time.
Form 2, you go as low down on the balls of the feet and bend the knees as much as you can comfortably. Yes, you hold the breath for about a second upon bringing the arms up, parallel to the ground. No, you don't lock your elbows or arms at all, you want to do it totally relaxed.
Form 3, horse stance is a double weighted stance. The weight is distributed evenly on both feet. This does not change with the arm movements. I don't know what you mean by variants. Just do the exercise as instructed.
Zen meditation, you can blink.
It would have been great if you asked these questions at the BEGINNING of the week and a half when I posted them instead of one day before the next lesson is going to be posted.
Again, watch the videos and stop overcomplicating things so much. Everyone else was able to practice the exercises, confident they were doing them correctly, based on my videos.