Well, it's not clear WTH Luke used for sources, but yes, there's definitely the writing of more than one guy in Acts. The style changes abruptly all over the place. The trial records are another example where people talk nothing like they do out of court, often right on the previous or next page.
I don't see anything in there that contradicts Josephus about those guys being a fourth sect, or an offshoot of the Pharisees. Maybe some Essenes did switch camp to these guys, as people often do, and maybe some were even among the founders, but it's still a different sect.
We don't really know WHAT the Nazirites were into, but the Pharisees were all about purification rituals too. So, since Josephus does tell us that the fourth group were agreeing with most of the Pharisee doctrine, I'm just saying, sure, it's POSSIBLE that James was a zealot.
I'm not disputing that, but there's more than one group of Xian Jews that the early Xians regard as heretics. And we don't really know which came from which earlier sect, if any. It's not that easy to identify them with the Qumran Essenes just because they're Jewish
But that's not what I'm talking about. And that's exactly the thing: Mark's Jesus talks to foreigners who don't join all the time, and even sends his apostles to talk to strangers who don't join. But he tells them to tell those strangers to keep the secret, and surprisingly enough they do.
I mean, it's not even just people who happened to see him do miracles on the street -- and also get told to keep the secret in Mark, for some weird reason -- but his Jesus actually sends his apostles to preach to total strangers.
Check out Mark 6:
7. Calling the Twelve to him, he began to send them out two by two and gave them authority over impure spirits.
8. These were his instructions: “Take nothing for the journey except a staff—no bread, no bag, no money in your belts.
9. Wear sandals but not an extra shirt.
10. Whenever you enter a house, stay there until you leave that town.
11. And if any place will not welcome you or listen to you, leave that place and shake the dust off your feet as a testimony against them.”
12. They went out and preached that people should repent.
13. They drove out many demons and anointed many sick people with oil and healed them.
That's not exactly being secretive to strangers, is it?
Wouldn't it make more sense to just write their oral traditions down? I mean, obviously they had at least one guy who isn't just literate enough to write stuff down, but he can even translate and adapt a gospel from Greek. Can't someone just dictate their own stories to that guy, if they actually have any? Just saying.