TLDR: You covered salient points, but missed the most important part. Taken separately I'd be inclined to agree, but together, it starts to tips the scales of plausibility to atleast someone with contacts/connections to IG/Cognizant

I would be tempted to believe that as well given I am naturally skeptical but that doesn't explain a few key points:

1.) How did said person know about some of the internal controls/details about IG moderation. We're talking ban duration, whether the penalty is reset vs cumulative (it's cumulative). Your thing about "reverse engineering" only scratches the surface. This person provided some pretty granular info about the effects of some of the moderation tools. I didn't only get one email, there was some back and forth, they just included the most interesting ones in the email (that most people [re: noninfluencers or technical people] could grok)

2.) the method you listed does not provide timestamp/posting time for deleted posts. Additionally, the timestamp was not in my timezone. It was in the timezone of the particular moderation facility that took action. Person also provided some info about moderation facilities that at that time had not been reported on by media. Subsequently, the media came out with a story (about a week/week and a half after the email revealing certain site info) about cognizant. Not sure how anyone would know that or why some random scammer would dig into that since it's such a far-out way to verify their claim (that they work there). Maybe they don't work there but know someone who does. Maybe they communicate with someone who does, unclear.

3.) Someone mentioned my email may be compromised hence how they got data. My email doesn't get notification from IG. Only notifcation about moderation action happens in-app. If they could hack into my app they would have just held it hostage for blackmail money instead of this round-about "pretend to be moderator" approach. Likewise if they had the email they would be holding other things hostage/extorting money in a way that had more teeth.

AND MOST IMPORTANTLY:4.) The very day that Journos reached out to facebook/cognizant for commentary about this issue (Huff post & others investigated, and like responsible journalists they tried to include facebook/cog in the discussion loop), the Mysterious emailer went radio silent. Previously he would communicate after a post was taken down, but after instagram/cog was looped into the story this person went dead silent. Even emailing him asking for his payment info via whatever bitcoin wallet or means he wanted to be paid yielded zero replies. What kind of scammer refuses to take payment/profit from his painstaking endeavor? Like isn't that the whole point? To pretend to the point where you get paid? Also the timing of his/her going silent? A scammer unaffliated with IG would NOT know about anything going on inside/wouldn't be aware of IG doing an internal investigation into the issue. Said person would NOT break communication just when the victim seemed willing to comply/pay up. This is the part that is most odd. The timing.

You seem to have some beef with HuffPost, but they were pretty thorough here. They reached out to instagram, facebook and cognizant for commentary as well as myself. They also consulted with someone tech savvy and looked into extracting data from the email, bit wallet info (never got to that step because the person went radio silent) and additional metadata. I know you have an axe to grind and it's easy to poke at some of the points -taken alone I wouldn't think any of these are particularly convincing (except the last point -what kind of scammer disappears when it comes time to get paid?), but together it's pretty compelling re someone who is either employed, contracted, or at the very least KNOWS someone who is employed/contracted.

The idea that they are holding out for a payout by building a reputation sounds like a fantasy. I purposely don't publicly talk about my posts removals to not attract attention to them (previous to this article obviously). There are plenty of girls who complain about it daily and exasperate for a solution on thier IG/Twitter feeds. This doesn't add up.

This.
No way they walk away at the payout.