I see. Thanks.
Two things, though:
This is a long time after both of them. The Yerushalmi’s story is about a grandson of רבי יהושע בן לוי. At this point, the religion with all its legends kicked off. They are the ones who conflated the two. The Yerushalmi is merely (mis)quoting the name that was used.
The other thing is that we aren’t given the name of בן סטדא. It may well have also been ישו, which helped in weaving the big story.