Correct.
(Although looking at the wiki page for Knock Off specifically it looks like there was some weirdness with it disabling the item in Gen IV rather than actually knocking it off. I’ll probably go with it actually knocking the item off, because wow that’s unintuitive.)
I’ll allow it this once, sure.
No problem there.
If she evolves, she has to use the level numbers for her evolution. So as a Crawdaunt she could be tutored with it at *checks* level 38 (FireRed and LeafGreen).