1. I think the Nihil are mentioned more in upcoming canon that slides into the timeline, but it's hard to keep track. They're new to me, that's all I can say for certain.

2. I think falling would be hard to learn because instinct says "OMG!". Like starlady said below, I also think it's an in-joke about how often Jedi are leaping out of things - speeders, spaceships, over cliffs, etc.

3. Yeah, it does look bad for her. There's a "doctor" on board who knows she's there, but no one else. Classic abuser cut-victim-off-from-everyone tactic and I don't like it. I hope we see a resolution for her situation that doesn't involve making it worse!

4. My guess is they think it could be her, but didn't realize she was still around. I could be wrong, I usually am on these sorts of details (LOL)

5. I liked the temple, too! I liked seeing the outpost life for Jedi. It's like a cross between missionary work (which has other sets of issues - at least here they were simply being available if needed and not pressing religion on anyone) and a kind of monastic work-study program.
We know there are more temples than just the one on Corusaunt. It's nice to see a time when those places are in use.