1) Would you be returning to the US to work for your H-1B employer. If so, without knowing all the facts, you should be fine. 2) I'm not sure what you are asking here.
(2) Yeah it's probably not a super useful question, just confirming AC-21 clock starts when the I-485 is filed and in spite of office closures / delays en route (my biometrics appointment just got cancelled) that remains unchanged.
