I don't think that electrolysis is needed for peritoneal graft.
The only reason for electrolysis is if the skin that is to be used for the vaginal lining has hair, it should be removed permanently before surgery to prevent the hair from growing on the inside of the neo vagina. In a peritoneal graft procedure the peritoneal tissue has no hair, so electrolysis is not needed.
The peritoneal procedure is not common for transgender surgeries. In the past it was almost exclusively used for cis females who had an inadequate vaginal depth. In such surgeries the external labia are already formed. In a transgender surgery the labia must be formed from other available skin, usually scrotal or other nearby tissue. If there is hair on that tissue, it must be removed or it will grow on the inside of the labia.
Electrolysis does not have to be insanely painful. There are a few electrologists who have injected a local anesthetic such as lidocaine that will totally numb the area for hair removal. This can only be done under a doctors supervision. Other electrologists use a numbing cream that helps reduce, but not completely eliminate the pain of electrolysis.
I am sorry that I cannot give you a better answer. In my dreams years ago, I wished that I could just walk into a doctors office and walk out a few days later just completely transformed. It never worked out that way.

Electrolysis hurts. Surgery hurts. Recovery hurts. However, when all this is behind you, the rest of your life is priceless!