I used the following McMourning Beast crew in a game of extraction against Outcasts (jack daw)
Im newly returned to the game and The Guild are a new faction having played Arcanists (mainly Marcus) previously, so his wave 5 upgrade really lets me use some of my old models!
I think it worked really well, ended up with a 10-3 victory. It was my first time McMourning and although we don't have all the poison tricks Ressers do I like the Doug/Seb combo for chipping away 3 dmg every activation.
I didn't go full out poison beast but more an all rounder due to scheme pool (I took covert breakthrough and quick murder on Montressor). Myranda and wrath or guild is great and reminds me of the Myrand-Imbued energies combo from arcanists. She turned into a Cerberus but I wanted to start with a blessed due to the filthy full heal combo with the nurse!
I'm thinking of ways to get the Jury in the list as there are a few mask triggers this crew likes (Dougs push on scalpel fling, leap on Cerberus, Myranda making beasts take an extra attack). Could drop Seb and not play the poison game at all, it's certainly something I'm going to try.