Topic: Travelling in cruise with EAD AP status without Mexico visiting Visa

As long as you have a valid EAD/AP status, you do not need a Mexico visiting visa if you're traveling to Mexico on a cruise. Your EAD/AP status allows you to travel internationally, including to Mexico, without requiring an additional visa.

Topic: Applying H1-B overseas

If your friend's H1-B petition with company C is approved, he can start working for company C as soon as the petition is approved, without waiting until October. This is because he already had an H1-B visa in the past and is considered a "cap-exempt" candidate, meaning he is not subject to the annual H1-B cap.