Regarding Disengaging from multiple opponents.
Personally I would require 1 combat action to disengage from multiple opponents as it's an oposed test anyway. If any of the opponents beat him then he fails to disengage from that opponent (Not sure if that's RAW, but it makes sense to me).
But he has another option, let's change that scenario slightly.
Barbarian with axe vs 3 guys with knives, BUT he knows in a round or so he has reinforcements OTW.
He COULD choose to OUTMANOEUVRE them for the entire round and that only costs 1 CA, if he beats them, they can't attack him, if any beat him then they get an attack, but he still has 2 CAs left to parry anyway.
But I probably wouldn't allow him to attack back as he's trying to outmanoeuvre them unless he gtes a Parry CM and chooses Riposte.
From what I see in gameplay, if you generally just decide to fight toe to toe and fight, you run a high risk of getting hurt.
When I run games I encourage creative thought in combat, so it doesn;t just boil down to opponents standing in front of each other whacking each other.