To work for employer the petition must be filed within the grace period, else wait until approval

Yes, when eligible to apply for OPT

H-4 dependents are not exempt from non immigrant intent issues.

Any valid and approved I-140 can be used for extensions beyond the sixth year

Working from a place not on the LCA is a violation of status and I don't see any other option.

If I-140 is approved and I-485 pending for over 180 days, per AC21, new job can be in same or similar occupation.

Possibly depending on whether there is an issue with alcoholism.

Yes, you can seek accountant position under NAFTA

In whatever classification it is similar you can post there

Your employer can pursue appeal or MTR towards cap exemption