Converting from h1b to F1 then OPT then back to H1b - is it feasible?

Question

I got my h1b approved and planning to do my Masters and graduate before my h1b expires.
If this doesn't work then i can do a full time schooling by changing to f1

1. is it possible to change from h1b to f1
2. can i apply for OPT again for MS , I am on OPT STEM
3. can I apply for  17 months OPT extension my 12 months opt expires after Master as I have not used 17 months for my bachelor

Answer 1

1. Yes, you will be able to file a COS back to F-1 on Form I-531.
2. Yes.
3. Don't think so, no. But ask your school"s DSO and see what he or she says about that.