How many times can the appeal be submitted?

You can submit as many times as you are willing to pay for an appeal for the same credit.

Yes, and it is not documented anywhere. What you will find in the Certification documents are first and final appeals. That implies a two appeals per credit maximum.

I confirmed with GBCI management, that you can have as many first appeals as you like, so long as you pay the appeal fee each time.

Oh, and a final appeal is when you decide the GBCI is incorrect about a denial. In a final appeal situation a group of independent "experts" consider the situation.

I nearly took the final appeal step for a Schools project for process water. The project included a student cafeteria and the kitchen consultant made an environmental decision to reduce water use by eliminating the standard food steamers for a cook system that did not require additional water use (braising pan).

The GBCI decide that only process water uses that use water could be claimed for the process water. Although we explained that composting toilets earned water use reduction credit and used Zero water, that was not enough. It was also not enough to provide the original planning and programming documentation showing that a steamer was indeed the school desire from the start of the project.

Process water uses must use water. Technologies that completely eliminate the water use cannot be claimed in LEED.

Non-process water uses that completely eliminate water use can be claimed in LEED.