True there isn't anything on Harry's sheet about being the Za Lord. But then his Aspects can change at any of the milestones he went through and he probably eventually gets around to changing one of them to something like I am the Za Lord or he might not have depending on how relevant it was to the story that he and his group were telling. Basically any trouble from it could always be compelled off of his Perpetually Broke aspect that he keeps having to buy extra pizza for Faeries every week. Really until it gets brought up in the fiction of their game by Contacts or Resources rolls, being the Za Lord isn't really worth or cost any Refresh points.
But getting back to the OP's question I'd say that the character's aspect "A loyal staff bound by blood, love, and bargains" should do most of the heavy lifting when it comes to dealing with the Pixie Army, Fae Major Domo, and any old family friends. Invoke it whenever you need a bonus when dealing with them, and Compel it whenever those bonds of blood, love, and bargains become an issue.
All sorts of juicy Compels leap to mind with that sort of aspect. Just what did your great, great grand ancestor do to bind a Fae to his family for all this time, do you need to do it again? Sometimes Pizza Guys are late, what happens then? Crazy old Uncle Eustace shows up at your door claiming that someone is after him and he needs a place to hide, what if that someone is a Warden?
Now if you want the Pixie army to become even more effective information gatherers then a pick up a stunt called something like "Pixie Spymaster" which could give you a bonus to Contacting rolls possibly either a +2 if it dealt specifically with rolls about the Fae or a more general +1 to rolls as you've trained them to pay attention to mortal comings and goings as well. Really the effect of such a stunt should depend on what you want it to do. But if you combined this with the Pixie's existing stunt you could get some pretty powerful access to lowdown on what's going on in Faerie.
If you want to lead them into battle remember that Pixies really aren't that dangerous in a fight unless you've loaded them up with a bunch of Aspects for them to tag using maneuvers. I'd say that most of your rolls involving such an army would be Contacts, Rapport, or Resources rolls, don't worry to much about giving Pixies rousing Band of Brother's type speeches with Presence rolls. Just get them hopped up on pizza, promise them more, and point them at something.