Responses
They know what he looks like because in the novel it was mentioned that they have a connection with their master. It's how they knew he fell into Möbius and spoilers they weren't looking for him from the start because if it were they would have brought him in Nilfeim the moment he fell and he wouldn't have to go through the trials if it were the case
I’m guessing it would take 5-10 chapters for this arc to finish. The reunion and the training with MC’s heroes, just thinking about it makes me giggle. ε=ε=(ノ≧∇≦)ノ