There's something that gets under my skin, heh, when I theory craft my Lucius crew and I find non-mimics therein. Certainly, you can't go wrong with Austringers or Riflemen, or whatever you feel like taking. But, the point is, I don't feel like taking them. Personally, I feel that the sole purpose for Lucius to take 'Surprisingly Loyal' is to run Guild Lawyers under the Neverborn flag. Each Neverborn Master represents a facet of Neverborn culture and how it interacts with human society, usually as a manifestation of one of humanity's primal fears. I'm rather taken by the uncanny, kangaroo courts, and smiles that don't reach the eyes. That's the facet of the Neverborn that Lucius provides, and while taking Austringers may be the fashionable choice for the competitive, I'd rather not have the success of my crew depend on a model that represents everything my chosen faction despises.
If you take a look at the models with the mimic keyword, you'll find almost all of them aren't meant to be played straight. Neverborn Lucius needs some finesse, no doubt. Sure, other Masters may do it better, but this is about style and theme.