If I have the AP (Advance Parole) and go to India and appear for H1B visa stamping, and if the visa gets rejected for any reason (or getting late in issuance), then can I return back to USA on AP after H1-B visa rejected in chennai.
Using AP, forces you to start working on EAD, losing ur H1B Status.
No. The Cronin Memorandum specifically contradicts this, and has been around for almost a decade.