To my knowledge, a good level 60 tank can solo most level 50 stuff if they really want to, add to that a level 60 healer and that should be more than enough. I three manned ifrit HM the other day for a friend who receny started the game and was at 50, while the other two were me on 60 heal and a friend on 60 tank.

As for novice network, I don't know how it is in your server but at least on mine there tends to be always mentors (and sometimes the longer standing novices) who like to jump in if asked to help some people get further in their careers.