Buddha was from India, not China. He was a real person. He went away from his village for a while, and when he came back, he was happy all the time. Everyone in the village wanted to know Buddha’s secret to happiness. People asked him and he said some really weird stuff (like “what is the sound of one hand clapping” – I know, that one isn’t from Buddha himself but a follower, but it is the type of thing that Buddha said). Others observed Buddha to see what he did and tried to emulate that. From these two groups stem the two major branches of Buddhism. Buddha, btw, never claimed to have any kind of divinity.
I would suspect that if Buddha is popularly assumed to have been fat, he probably was.Buddha regularly said one thing and did another. Having said that, it does seem unlikely that he was fat. Perhaps he was fat at the time that he became “enlightened”?
PS: Fortune cookies? You realize they were invented in San Francisco (albeit San Francisco’s Chinatown) and not China, right?