You know, I'm going back on my thought that Fritz and Heinrich have to be brothers. I just realized I wrote a crack Corporate AU of Moses and Aaron back in the day, and I specifically had them not be brothers (nor Miriam their sister) for what I imagine are much the same reasons you didn't envision them as brothers in your corporate AU. So... yeah, either way is fine with me, and now I'm actually leaning a bit against them being brothers (and Fritz just being... THAT BOSS).

(Still not wanting Fritz/Heinrich for this AU; I actually want it even less if they're not brothers.)