Agree with colleagues, yes you can travel.

I agree with my colleagues that category doesn’t change but I would suggest if your parents can afford then they should apply as well.

I Agree with my colleague that you should apply for I-485. I suggest to consult with an immigration attorney.

Unfortunately not because of entry date.

Consult with an experienced immigration attorney asap. May be you have to reschedule the interview and streamline issues/ answer before appearing...

Agree with my colleagues. Please consult with a Canadian Lawyer.

If you are US citizen then new born can get US citizenship. If you are Green Card holder then you can update it during NVC.

Yes can proceed with citizenship but MUST consult with an immigration attorney.

Consult with a local attorney and send them a written notice.

Nothing to worry. Most likely it will be approved.