My current H1B stamp is expired so I need to go for stamping whenever I go to India.

Current employer A.
Have offer from employer B. H1B transfer just got approved.
Resignation not yet given to employer A.

Questions
1. Can I go to India now and get my stamping done with employer A's approval and come back and then resign? Will B's approval remain valid in this case?
2. Or should I go to India and get stamping done in employer B's name. note that I would not have any pay stubs from them.
3. If I get stamping done using B's approval, Can i come back and then resign. Note that I might run one more payroll (during notice period) with employer A.