L2 to F1, need help

[zmch]

I am now applying for my L1B visa. My wife has got her F1 visa and is going to study in the US this summer. Some questions here:
1. Whether she can change her visa to L2?
2. If yes, what time frame is appropriate, before entering the US or after?
3. She is attending a one year program so is it possible to change her F1 after her graduation? (i.e. one year after I get the L1B)

Thanks!!

 

[GotPR?]

1. yes.
2. a few months at least.
3. Yes if she filed L2 before F1(I20) gets expired.