Still, that means that we're either going to implement him as he's known from WitN where he isn't an "Iron Hills Dwarf" any more, or we have to come up with a younger Version of Farin that fought in the Battle of the Five Armies. But at that point we might as well design our own dwarf and give him another name.
I like the general idea of implementing different "lores", but I don't see any direct gain here sorry...