Further free fall testing:
Thunder, Gale, and No Guard can hit pokemon in free fall.
Escape Button cannot activate while in Free Fall, but Red Card can.
I'm next going to test with a No Guard Dragon Tail to find out if a free falled pokemon can be forced out, and what happens if they are.
Edit: When a choice item is used and then magic room is used, the choiced pokemon can switch moves normally. However, when Magic Room ends, it is again choice locked to the original move that it used before trick room. You don't get to pick again.
Pluck, Bug Bite and Trick work normally under Magic Room. Natural Gift and Fling fail.