Things I Think Are Good To Have In A Ref Team: (one person can have more than one role)
1) Consistancy Ref. Consistancy Ref knows everything. Consistancy Ref reads everyone's downtime and puts notes on other downtimes when they're about to collide with each other. Consistancy Ref knows who is attending interactives / linears and keeps an eye on them to see if they are getting enough plot / shinies / whatever they want out of LARP. Consistancy Ref knows where all the NPCs are and what they are doing, and what public or semi-public events are occurring in the city and surrounds, so they can provide notes about that if people downtime being in the right place at the right time / letters from people's families or friends if they're near an interesting occurance, etc etc. Consistancy Ref should probably not be assigned individual people to send out downtimes for, or individual plots to run, and should probably be the one who stands around in the kit room briefing people and dealing with people leaving the bar to go places, because they know what's going on out in the world, and need to be free for the other refs to bother if someone's sending messages out of the bar / ritually talking to people etc.
2) Diplomacy Ref. Diplomacy Ref can deal with angry / upset / overtired people. If there is some kind of dispute, Diplomacy Ref understands how to construct a compromise and what language to use when describing the compromise to the involved people. Diplomacy Ref does not accuse people of whining and can calm people down without actually committing to anything so as to buy time for the refs to come up with a consistant patch to the problem. If any of the other refs find themselves in a socially awkward or intimidating situation with a player they can go and get Diplomacy Ref to make it all okay again. When there are new players, Diplomacy Ref goes and says hi and helps them make their first character and introduces them to the system. Diplomacy Ref should probably mostly be a yellowjacket so they can run over and deal with problems while they're getting out of hand, but this might be difficult because they are probably also Awesome At Playing NPCs ref.
3) Plot Ref. Plot Ref has awesome ideas. Not only do they have awesome ideas, they have so many awesome ideas that they can pick the ones which fit the niches that require more plot in the current environment, they understand how plot works so they give it plenty of handles and know who they're aiming it at, and they are happy to rewrite their precious idea from scratch when someone comes up with an entirely different way to approach it than they'd thought of, or abandon it if nobody is interested. Plot Ref is also an endless fount of knowledge, but their knowledge is made up on the spot to fit the direction the PCs are trying to take their plot in (and passed under the nose of Consistancy Ref to make sure it doesn't contradict anything important).
4) Logistics Ref. Logistics Ref makes sure the interactive and linear plans show up, the radios show up, the props show up, the right bits of the armoury are available for the linear, the downtimes are sent out even when three of the refs are ill and haven't done them on Thursday morning, the Gossip is written and gets to the printer on time, money physreps are produced, there's a place and time to have a refmeet that everyone agrees on, the exec know that we want a particularly large room for Interactive 5 this term, the society knows that we're planning a nightbash in week 3 and a Royston expedition in week 6, emails to the society that the refs have promised actually go out, etc etc. Logistics Ref also makes sure that we think about NPC kit and all NPCs have distinctively different kit / knows the rules for what kit designates 'Incorporeal', 'Black Demon', 'Nightmare' etc etc.
5) NPC Ref. NPC Ref is good at playing NPCs. They are generally a good actor, quite confident, and also capable of making things up on the fly in such a way that it is not impossible for the other refs to patch over the gaping holes in continuity this makes. NPC Ref is probably also good at administering the more talky kind of rituals. Everyone can easily distinguish between NPC Ref's different NPCs just by body language and accent and so forth, even when both of them are clad in indistinguishable Armory Katmari (which the NPC Ref should know not to do anyway).
6) Flange Ref. Where Consistancy Ref looks out for the consistancy of the setting, Flange Ref looks out for the consistancy of the system and the economy (such as it is). Currently this is mostly not the 'shillings' economy which is so thoroughly trashed as to require a lot of rescuing if it's going to be meaningful again, but the 'magic/spiritual/alchemical/flangy items' economy. Flange Ref looks over any things with special flangy powers that the other refs want to introduce, or the players want to find or create in a ritual or rite, and weeds out the ones which turn out to be hilariously broken. Flange Ref also adjudicates things like UF or Overcast, tries to make sure refs are fairly consistant answering Talk To type effects, and makes sure that linears do usually hand out more treasure than they require as input. They also answer questions of the form 'can I buy a flangeitem / potion / scroll / blessing from an NPC and how much will it cost?' (with consultation with the Consistancy Ref where necessary).
7) (added by Valtiel) Loud Ref. Sometimes, large groups of people need to be made to do complicated things in short periods of time when they'd really rather be doing something else. This is what Loud Ref is for. Loud Ref is more than just Loud, they are clear and concise in giving instructions, adept at herding cats, unashamed to shout down a room full of people, and willing to pitch in as hard as everyone else with whatever the task at hand is. If Loud Ref is also Diplomacy Ref, then that's great, but that's probably not the case. Loud Ref gets the armoury put away, organises teams of monsters at short notice, makes sure the linear starts on time, makes anouncements - or at least silences the room so anouncments can be made - and can actually stop a roomful of larpers from faffing.
There are almost certainly more responsibilities than I have thought of here but it seemed like an interesting way of looking at things - particularly, ref teams seem to underestimate the amount of work Consistancy Ref does and the need for Logistics Ref (and the dangers of leaving NPC costuming to the NPC ref doing armory katamari on the day!).
8) Head Ref (added by Zebbie) I think that the Head Ref overlaps with, but is not quite the same as, Logistics Ref and Consistency Ref. It is the job of the Head Ref to make sure that the ref team are fulfilling the basic duties which they accepted when taking on the role of ref team - running interactives containing plot, running linears, answering downtimes, writing the Gossip, and so forth. If other refs are sick/away/slacking/etc, the buck passes to Head Ref to make sure that the output of the Ref Team continues uninterrupted, and there is no 'denial of service' to the players. Of course, this can be done by efficient delegation/cat herding to other people, as long as the correct results still turn up on time, rather than meaning that the Head Ref has to do everything themselves. However, it is the job of the Head Ref to see stuff like 'it is Thursday morning and there are downtimes not yet sent out' themselves and fix it rather than waiting for other people to complain that the ref team is failing. They could also be described as 'external ref', in that their job is to look at the ref team like a player does and make sure it works/fulfils its functions.