Since you have an immigrant intent, it will be very difficult for your spouse to get a tourist visa.

Spouse can be added as derivative at initial filing or when application is pending. If married after AOS is approved, you will have to petition...

If the GC holder is unable to maintain residency, they can always look into other options to enter without legal issues.

Yes, you will need a visa to enter. Look into wait times for H-1B at your Consulate.

May be hire a lawyer first and they will walk you through the steps. Horse before the cart.

Employer can file H-1B if you wish to work on H-1B

It appears you will have to consular process at some point

It is best not to apply for debit card in personal name for any company unless you are an employee of that company.

There is no restriction on when you marry.

If you were terminated or ended your employment with previous employer, they should file again