The L1 visa allows "dual intent' which means you can be admitted even if you may decide later to file to adjust your status. You can either file...

A person in the US on an H1B is permitted to be enrolled in classes. There is no limit to the subject matter.

I have never heard of anyone doing that and I cannot believe it would be approved.

It may help your spouse to continue to live in the U.S. and become a U.S. citizen.

No, working another job when you have an EAD does not violate your h1b.

No. You cannot work for a foreign company in the U.S. without a work permit.

Applying to extend your OPT will not harm your application for adjustment of status.

It is not, by itself, a basis for denying the application.

You can ask the judge for time if you wish.

Yes, you can file a VAWA application while your I-130/485 are pending.