what i wonder is .... why do you care so much if its one faction or multiple factions / npc group?
many a factions were created and established long before the admins decided to make it a 1/npc faction rule. - and it would be impossible or outright unfair to re-apply this rule backwards... cause who is to tell who deserves official status and who does not.
anyway - is it detrimental that some factions are led by multiple people? ( asking someone of any of these factions can usually turn up sufficient people to talk to in case of trouble ) - FR5 are based on a global detrimental behaviour against the factions root characteristics - so it also does not matter if it one or many factions.
generally - trying to apply the 1 / faction rule backwards would cause a lot more trouble than keeping it that way.
when it comes to inactiveness - there are factions that do not satisfy the demands anymore indeed. - but sometimes the rules are bended or ouright broken to no detrimental effect. - its just like that... not every rule that is broken harms gameplay, not ever rule that is obeyed to the letter benefits gameplay. - its usually the admins who decide which ones can be bended and which ones cannot. - that is their responsibility
edit: i m not asking you, cause i think there is any malicious intent behind your demands - but rather to find out if there is a real problem with multifaction representation that are simply overseen.