I am a physician currently on an H1B visa and will be completing my residency program this summer. I already have an employment offer with a fall start date. My husband also has an H1B and is awaiting Perm Certification.

a, How can I transition from my current H1B ending in Aug to a new H1B starting in Oct/Nov without going out of status?
b, Can I transfer to H4 at the end of my residency and then back to H1B?
c, Are there timing restrictions on when I can file H4 and/or file the new H1B?
d, If my new H1B is effective immediately after the end of my residency and I start work in Oct/Nov (2 months later), will this affect my GC application if there is a hiatus when there is no pay slip?