No, it is actually MORE believable if the scumteam is 3 people
We have a flipped roleblocker.
We have an existing poisoner.
We have a likely scum gunsmith.
out of those 3 the only one who actually gives any meaningful result is the roleblocker
the gunsmith is the equivalent to a scum miller for the other gunsmiths, so it's hard to tell if town/scum gunsmith from a gunsmith result.
the poisoner is the equivalent to a scum godfather for the other gunsmiths.
So only 1 scum actually gives any meaningful result to the gunsmiths and town doesnt seem to have any other way to figure out who's scum other than by day play entirely coz the investigatives are useless.
So an alignment cop can easily find the scum gunsmith and the scum poisoner and tell the difference, likewise can find a town gunsmith
Anyone with a "not gun" result can still be a scum poisoner
Anyone with a "gun" result that is a claimed gunsmith can still be a scum gunsmith.
An alignment cop doesnt care they'll get the alignment and i doubt there are millers or godfathers if the gunsmiths are already in a bad situation wrt investigations.
Just like the vanilla cops of last game, any non vanilla result didnt mean much for the town.
Ergo, i believe that Katsuki is the role he is claiming. And if the inno on muffin was enough to cause scum to poison him, i also believe that muffin is conf town.