It doesn't seem likely to me. I'm sure there were a bunch of sects and cults around all the time back then. I don't see why an historian would necessarily mention them.
All the historians I just mentioned dealt with that topic. What you're proposing, that the actual Jerusalem church was comprised of followers of a proto-Jesus who had lived 200 years before the period we're discussing, isn't worth introducing into a discussion like this unless we're willing to examine the idea and see how it holds up to a little logical speculation.
Put it this way: if there actually were a cult or sect centered around another Yoshua who lived sometime around 200 BCE, that would put there emergence at right about the same time as the emergence of the Essenes and the Qumran sect.
Cults are organic, they either grow of whither and fade away into obscurity or (more often) extinction.
Almost all cults that are centered around an actual, living human being die off shortly after the death of their central figure.
The few that don't tend to grow and attract more followers and greater attention, acceptance, and recognition. As with any organic entity, the basic rule for any cult or sect is grow or die.
So basically, any cult that had managed to exist for 200 years would have had to have grown substantially. At least to the point where they would have been known and noticeable, especially in a setting as focused on religion as first century Judea.
And even disregarding all of that, Josephus talks about several cults and movements centered around Messianic claimants during this period.
Given all that, it just seems unlikely that any cult or sect such as your describing---especially with an established history of 200 years behind it---would have escaped notice completely.
