Time to give scum!O the same treatment as scum!sudgy and scum!Dylan.
Possibility 1: He guessed the right game and ended up at sport #2. It seems a bit unlikely if he'd stopped playing before the game happened, and it looks like he wasn't involved between M13 and M100, and barely existed elsewhere on f.ds at all in those intervening years either.
Possibility 2: He really was at draft position 21. This makes total sense for someone who doesn't know any of the newer players, and it's also entirely possible both with his claim (because Galz had already said he was draft position 20 and slot 11 by then). It's also looking entirely possible for him to have picked up either roleblocker or strongman from draft order 21, because we have no evidence of any townies having gone for slot 3 or slot 8. The only thing that makes this marginally less likely is the fact that the lowest-placed scum would be bidding for a decent power role (i.e. if scum!O was bidding for RB, what were the higher-placed scums bidding for?). Maybe the higher-placed scums tried for roles that might be more in keeping with hiding out as town, though, and got beaten to the spots? I think this option isn't actually too unlikely.
Possibility 3: O was at some other position in the draft order, and traded down to Calamitas's vacant spot, or to the spot held by another scum goon. Totally possible, and he doesn't even have to have claimed to have bid for the same slot as that scum for this to have been possible, because Galz had claimed draft order and slot a long time before O claimed his slot. This is another totally possible option.
Possibility 4: O was at some other position in the draft order, and just took advantage of the fact that Awaclus left him till last in the claiming order to claim any old unclaimed place. The only people who claimed a slot after O were Awaclus, e and RR, in that order, and we already know that e was happy to try fake-claiming in that position. Sadly, because of Awaclus's not-really-explained tunnel, we never had the chance to catch him out in any part of the claiming exercise.
Have I missed any scenarios? Several of these seem quite a lot more possible that any of the Dylan/sudgy breakdown elements, so overall, I think O looks more likely to be scum if we take this kind of analysis in isolation. (Though I'm not suggesting we should ignore all the other kinds of evidence... I'm just compiling the stuff I'm better at thinking my way through, at least when I'm awake!).