You can do that. However, you then must..
a. Backup supposed credible evidence with historical accounts
b. Show how your theory turned into a religion or "cult" in the region.
c. Present a theory of "man to mythic" evidence using text or historical evidence
d. Supply evidence that the "cult" was a logical step from existing religion/beliefs of new "occultists".
e. Supply evidence that the earliest converts held the crucifixion narrative as valuable to their religion.
Otherwise....is your speculation reasonable?
O.k. my opinion, that scenario presented doesn't make sense to me....
Why?....
a. Timeline. Far too short of a timeline for a "mythos" to arise of that nature
b. Area. There was no geographical separation, makes it far more difficult for a fictional narrative to become literally a new religion without major criticism.
c. Pre-religion. These were basically Essenic type believers with, if we believe Josephus, "Gentiles".. regardless, this new religion to all accounts was similar to our austere Protestantism, if we read early descriptions. Does that sound like a "crucifixion cult" type of environment?
d. 'Crucifixion type mythos' are not regional to that area, very different type of religion, it is doubtful these early Essenic / Nazarene believers would have "created" that sort of theology. Rather, it would more likely have been already an existant part of the beliefs ex. Christianity as we know it traditionally.
Again, if you aren't a "believer", it doesn't mean a scenario with simply the miracles removed makes sense, either.