1. The Yerusalmi mentions JC’s full name only masiach lefi tumoi in this story which gives even more credence (if any is needed, when reading a clear Gemorah!)
2. Talmud Yerushalmi is (a) uncensored and (b) probably 200 years older than Bavli whereas these sort of agedetas in Bavli were heavily censored and are more likely to be wrong textually or contextually than the Yerushalmi until you look at the defusei yoshoni
3. We clearly are given the name of ben sitta – the Gemorah in Shabbos 104b says that it’s ben pandira, and the Yerushalmi says this is JC
4. The Ritva is unequivocal that JC’s full name is יש״ו בן פנדירא and I believe the Ritva knew how to understand a Gemorah 🙂
Your theories about there being misnamed legends about early xtians and that a Gemorah would repeat errors in these “legends” are ust that – internet forum theories and don’t stack up next to a Ritva. (Although of course, Tosafos does disagree but clearly not because of your “legends theory” but simply because they were missing some of the Yerushalmi!)