What I know about Henesys PQ is very limited so forgive me...
You can do it from level 10 I think, and there's no max level limit. First part of the PQ, you hit plants and gather seeds, with them I have no clue what you do I just dropped em on the ground like everyone else -_- After that a bunch of Flyeyes and Stirges (thought very weakened) come flying in, trying to kill a bunny that's in the middle of the map. You can't Heal the bunny, and the point of this is to have the bunny survive for like 10 minutes.
I did it once, and it was boring (personally), and the prize wasn't that great either (HP food), and it wasn't worth it for the EXP (then again I was level 36). Dunno if it's still possible to do it, I thought it was an event :?.