H1B Consular Processing while B2 is filed

Hello - I was laid-off last month because of the ongoing covid situation. Its been more than a month and I do not expect to find an employer and get the visa transfer process started in 2 months of grace period.hence I am starting the COS from H1b to B1/B2.

Assuming that I find an employer after 60 days of grace period and by that time COS from B1/B2 is filed but not approved.

I had two questions in this regard:

In this case ,can an employer file a COS to H1B or would I need to go through Consular processing?

In case of Consular processing can I work on receipt or would I first need to attend a consular interview before starting work with the new employer?