I would love for it to be Glenn or Abraham or Sasha and Tyrese. Would certainly make this show more entertaining if they brought in a crossover character from TWD.
According to what he said, I guess they could bring someone from fear to WD. I just guessed it would be from WD to fear. There are some very interesting fan theories out there. I won't mention in case they are considered spoilers, but it is neat to read.