I find this entire thing incredibly depressing and am starting to regret getting pulled into the saga so early.
As far as Tyler and JM concerned, JM posted that he and Tyler have agreed to settle this privately; as long as Tyler feels fairly compensated, I doubt we'll hear much more from him.
As for what we as the community should feel about what JM owes in this situation...
IF Tyler knew JMs SN on that site (and while he originally posted that he knew JMs Onbet name, he referred to it as his "network SN", so it's certainly possible that JM told him it was his SN network wide)
Then this is clearly a case where 100% compensation was due.
IF Tyler did not know JMs SN on that site, the fact that JM was playing on a site pro account becomes the deciding factor.
Tyler told me he had no idea who Girah was, but later clarified that he had no idea who Girah was when the match started - he Googled the name at the beginning of the match. So he clearly knew he was playing a site pro, and ergo somebody good, so some are arguing what's the big deal, he knew he was playing a very good player, and decided to play for those stakes and lost, too bad, so sad (and FWIW, while Tyler said ~$40K was a lot to him, I never got the impression he was busto without it).
However, Tyler would never have played vs. JM, and JM knew that. If Tyler had sat down vs. just a random SN, because you can have different SNs on different Merge skins, he'd have a right to feel scammed, because JM knew that he would never play him, but not really much recourse otherwise, since theoretically any random COULD be JM.
But he didn't play a random, he played a site pro, and quickly discovered that. He believed he was playing Jose, who clearly could not be JM (hah!). Which is why the fact that JM played on a site pro account on a skin where he's claimed not to have an account become relevant. Tyler had ever reason to believe there was zero chance he was playing JM (since the SN he was playing against was linked to a known site pro), but he was playing JM, ergo he was cheated.
FFS, all JM had to do was make his own Lock account and none of this would be an issue.
Sorry if I wasn't entirely clear last night (or early this morning, as the case was). My brain was complete mush and I was in a lot of pain. We'll see if I do better today.