If so, can use use the axle-mlunt derailleur even on a bike that doesn't actually have a derailleur hanger (one that was designed as a singlespeed)? I don't see any reason why this wouldn't work, but I've never actually used the saint or hone components.

Also, can you mount a saint derailleur on a hone hub and vice versa, or do they only work with parts from the same group?