Can I use an Advance Parole to go on vacation outside the United States?

Yes, you can do so. Advance parole is issued solely to authorize the temporary parole of a person into the United States. The document may be accepted by a transportation company (airlines) instead of a visa as an authorization to travel to the United States. An advance parole document does not replace your passport. Advance parole is most commonly used when someone has Form I-485, Application to Register Permanent Residence or to Adjust Status, pending. If you depart the U.S. while your I-485 application is pending without first obtaining advance parole, your case will be denied unless you fit into a narrow exception for those maintaining certain nonimmigrant statuses.

Yes but you must follow the terms of the AP. Vacation is never suggested for immigrants who do not have their green card and even when they do, sometimes very long vacations can be deemed to be abandonment of the green card. Speak to an immigration attorney if you don't have one yet.

Sure, provided you do not miss the interview as you are away.