Can H4 get a TA ?(Urgent!!!)

I may not graduate on time this Dec., but just submit 485;
Since many people tell me that F1身份，提交485後I-20 can not延期, is it possible for me to change to H4 1st, then get the degree?
Is it still O.K. for me to get the TA from my department? Can I use the fee waiver?
Can I apply for OPT? Since many say yes, many say no. (Even though, I was told you can not be a part-time TA under OPT)

Waiting for suggestions! Bowing...

Your help will be appreciated!