Next time we have birthday or holiday celebrations, might we have a figure or two that can only be obtained in the campaign? My idea is that the figure would show up in the Hidden Bandit's stash, or in a separate embodiment of that feature. I believe hunting it down would require at least as much effort as winning a league pod, as either can be simple or very difficult. Now that we have co-op, we can show them off while still playing PvE! Any "contest only" figures might do, but if new figures would be made, I'd suggest something in a Dungeon Delver (rather than Arena) motif. I think many PvE players would appreciate the gesture as much as the costumes.
We probably won't add PvE-obtainable costumes by Halloween (it's only a month away at this point) but this is a good suggestion. I'll keep it in mind. And we have some figures we're looking for excuses occasions to get to players—dark elves & demons, I think.
A figure in his stash? Make the figure the bandit himself! (human priest or mage then i guess, given the lack of rogue class)