The marriage certificate would certainly be helpful.

Changing status to TD, by itself, should not affect your ability to get an L1. Living in the U.S. and not working for an extensive period of time...

It's not allowed. You could try to get a concurrent E2 if you ae from a treaty country.

You have sixty days grace period to find a new petitioner. The employer can, and must withdraw the H1b if it has no work for you and cannot pay you.

There is no way to know for sure, especially since DACA is discretionary.

CIS takes about one to thirty days to send the notice.

Could be it was one of the application CIS sent to storage for the duration of COVID. They are now reopening those files.

Chances are that it was sent to one of the service centers that CIS shut down for COVID. They are reopening those and scheduling them now.

It seems to be well within the normal processing time.

The short answer to your question is yes, you must answer all questions truthfully and there is no exception for reporting incidents that happened...