>>1. There was someone with a popular name who gained an element of noteriety at the period. Some time later the church that was being established picked up on this noteriety and decided to use the character as a figurehead for their religion. Using bits of history and bits of legend they start to build a believable story.<<

So they already had the religion, they just needed a figurehead for it? Ins't that the same as saying there was no person this religion was based on?

>>2. A very popular name at the time, for some reason, fell out of favour for a year or two. Some time later the church that was being established decided to pick a name that had not been used in that period and make up completely unreleated events. Instead of relying on events that some people had heard about they chose to start from scratch and forge completely unverifiable evidence.<<

They didn't rely on events of witnesses because there were none. They took a mystery religion and its various rituals and watered it down into useless fodder for the masses.