TL;DR: OP is salty?

If anything, these requirements are way too easy. Over 90% of my FC is already qualified without doing anything.

Oh, and yes you need to have a Tank a Healer and a DPS if you want to teach your mentor. Why? Because trying to teach someone to DRG without having the perspective of how things play out from the other 2 ends of the job-spectrum is terrible. Tanks who have played healers and DPS are generally better tanks (Because they understand how Healer DPS and DPS positional works), etc.