Much more important are joint taxes, leases, bills, bank accounts, photos l, of you and your wife and affidavits from family and friends

Quality over quantity. No need to give kitchen sink but anything relevant and expected .

Theoretically they are allowed up to 120 Days by regulation to respond. They dont always meet that.

It appewrs you are a citizen. You can file Form N-600 for a certificate. Uou can also apply for a US Passport.

The regulations allow up to 120 days.

You couldnt travel with the travel notice but can with the advance parole document.

However they phrase it - the way to resolve is wait for letter and supply whatever they ask in the time frame they give you.

Based on your facts you should be able to apply for H-1B visa in Canada. However, they have the discretion to make you process in India.

It is possible. One way is to set up an agent and make a contract between you and the agent and then contracts between you the agent and your...

Yes. It is a potential issue. Why would you seek advice after filing instead of before?