On that leak it is worth noting that a small amount of insiders knew about Plant but then again, it’s possible he was piggybacking. Don’t exactly know who it might be because I don’t think Ryce and Vergeben said anything but they claimed that they knew. There was a 4Chan leak everybody overshadowed.
I think this leak lives or dies by when the source knew Terry was coming to the game, specifically if there's any evidence they were firm on that decision before the Terry/Hayabusa post on /v/ and obviously before the SNK info Nintendo leaked. Honestly at this point we could have the same guy on our hands - Papagenos' leaker and the Terry/Hayabusa /v/poster, just trying to keep face after getting the trailer wrong but getting Terry right by luck.