How to share apps between 2 iPads with 2 different iTunes account in 2 computers?

I apologize if this has been answered somewhere but I've spent a lot of time researching this and none of the questions exactly match my situation.

Situation: I have my own iTunes account, Mac and iPad. My Mom has her own PC, iTunes account and I just bought her an iPad.

Issue: I would like to share some apps with her, without her having to buy them all over again. Since I'm paying for all her app purchases anyway, I would rather not pay for Angry Birds twice. She has her own apps and music that I have no interest in, so we cannot share 1 iTunes account.

This is what I was thinking of doing from all the research I've read:- Since I can authorize up to 5 computers or 10 computers & devices from 1 iTunes account, can my Mom sign out of her iTunes account on her PC, sign in to my iTunes account, download all the apps she wants from my account. Then, she signs out of my account, back into hers and sync her iPad.

Questions:

1) This (should) mean that her PC is now authorized with 2 iTunes accounts - hers and mine. In other words, she gets to keep all her content in her iPad plus whatever apps she wants from me. Will this work?

2) It wouldn't wipe out all her apps/music/photos etc during the sync, will it?

3) Will update to apps I purchased in my iTunes account automatically also update in her iPad? Or will the update only happen if she signs out of her account and in to mine again.

4) If someone knows of a better way of doing this, I'd greatly appreciate it. Thanks much

Jeff