basicly its most probably allowed. - we must not mix two different things here - the level of rules and the level of roleplay.
if the char is zoner IDed and zoner IFFed - he MUST act according to the zoner canon RP.
if the char is as well an order agent - he can most certainly be that. but if for example the order goes forth and stages an assault on - for example - a LSF group that is up to no good... the zoner IDed char MUST NOT participate in that assault, as it would contradict his ID. ( even if his RP as an order agent might not only allow but also demand to support the order )