How can an F-1 visa holder get married without compromising their I-485 process?

It is not clear whether you have filed I-485 based on marriage to a US citizen or green card holder or based on employment-based category. Marriage should not affect your pending I-485. You may interfile a copy of your marriage certificate into your pending I-485 case. You may apply for EAD and AP as part of your pending I-485 application if these forms have not been filed concurrently.

I understand your are an F-1 student with a U.S. citizen fiancé. If you marry, I assume your fiancé will file the I-130 petition for your benefit and you will concurrently file I-485, I-131 and I-765. Your I-131 and I-765 will be processed while waiting the process of I-485. If you file the I-485 you are declaring your intent to remain a U.S. permanent resident. A condition of F-1 student status is that you have residence in your native country to which you will return following completion of your studies. Therefore, once you file the I-485, you will no longer be eligible for F-1 status because F-1 is not a dual intent visa. If something goes wrong with the I-485 approval, you will be without status.

Congratulations on your future marriage. If your fiancé is a US citizen, your status will change to adjustment to permanent residence once you file the I-485 application. Within six months you will receive the work authorization and advance parole. In the meantime you can still attend university until you receive the work authorization and advance parole document.

Yes, you may apply for interim benefits of work and travel while your family-based adjustment is pending. If you continue to maintain your F-1 then you can revert to that if the adjustment is denied for any reason.