How about entertainment folks, not just the big names, make a point of visiting booths and introducing themselves to the boothies at hand, then tell any customers around that you learned that Lady Francis, surely the loveliest lady of the court after her majesty, greatly favors the necklaces, the port, the chocolate, the wreaths, at this shop. Or the mayor's mother-in-law, or the head of the constables. Or maybe mention that the puritans are greatly enraged that this booth has been allowed in the village.

Then tell the boothies any gossip you think they should know.

Oooh, ooh! (waves hand á lå Horshack)

How about the noble families set up an adopt-a-booth patronage program? In exchange for the "patronage" of a particular noble (which they can display on their wall, talk up, and use as promotion) the booth agrees to promote some aspect of that noble (a "portrait", an information sheet, etc.)? The booths could have the opportunity to engage in this, or not, as could the nobles.

I would say...
Obviously every booth owner/worker may not want to participate in the entertainment, though there are some who may.
Imho, that should largely be a choice, as long as the booths are complying with basic standards of dress and ambience appropriate to each faire.
I think, though, that the original question was more, "How do the departments keep each other informed, so nobody's left in the dark?"

My idea: literature.
At faires I've been at where the faire ownership and/or entertainment management disseminated comprehensive literature to the booths, boothie/actor relations have been better than at those without.
For example, at Texas, a comprehensive participants' guide is given out to everybody, acts, booths, actors, push monkeys, everybody. It includes everything from costume standards and resources to booth contract issues and all sorts of stuff in between. In addition, each vehicle who comes through participants' gate is handed a copy of that weekend's news from the kingdom, which announces attendance from the previous weekends, winners of contests, media visits, special events in the plot, etc. Programs include color photos of all the groups in the cast, and stage acts, as well as pictures of foods available at the food areas, and a detailed map and schedules.
So, anybody who wants to can know what's going on and who's who, without having to have a huge meeting.

I've been at other shows with less pamphleting, and those of us stuck in a booth have no idea what's going on.
(yes, we're stuck there, one can't close shop in order to go explore the faire)

So, give the booths the news, what's happening when and where with whom, feature a few characters in each issue, with photos, so hapless salespeople have a clue who's that loud person and how does one react to him/her...

That way we're all on the same page, 'cuz everybody has the option to acquire knowledge if they want it.
In addition to allowing the boothies and cast to interact, it also helps the boothies to not look like idiots when asked for directions, times, etc. I try to keep a program handy in order to be most helpful to all my potential customers.

I think that forcing character interaction on folks who just want to sell their wares will just be seen as rude, tend to alienate certain boothies, and reinforce the thought, "those annoying self-important actors, they think this whole faire is here just for them... grrr..."

However, I think celebrity endorsements are funtastic. Hey, noble types! Plant your velvety self in front of a booth for two seconds and declare, "I'm Lord Rich Nob, Second Earl of Toffs, and I approve this merchant." If the booth minds, you'll be out of there quick. If they're into it, you could come back next time and extend the bit to a brief commercial (if they sell chausses...).

Hey actors, you'll know a booth doesn't mind you stopping by if we greet you as you pass. "Good morning, Rattie Ragpicker! Hello, Baron von Poofy Pants!"
If we don't know your name, sorry. Betcha common merchants not knowing all the visiting nobles by face and name is period.
If we're too busy doing our jobs and helping our customers, not sorry. That means business is good, wee!
If unsure, wait for a slow time when we have no customers, and just pop in and ask if it's ok to do your acty thing hard by. If it attracts business, we're probably fine with that. ;) If it obstructs the walk way (sure, the streets are your stage, but they're also streets!), or distracts folks who are shopping, that irritates us and makes us complain. Either way, if you ask, you're somebody we've talked to, instead of some pushy actor.

Other thing: participant-wide opportunities for off-hours socializing. At PA, after gate closing, the pub stays open, and lots of folks go hang out in weekday clothes, and chat about their days. So the herb shop girl who's giving an Earl a ride home can have a beer with the privy attendant, a musician, and Shakespeare, and we can all dish about our days, our customers, our bits, our shows...etc. It helps with the cohesion. Beer helps, too. :)
So, invite the boothies to your party. We're fun folks too. Then we'll know you, and be more like coworkers than strangers.

(what's this boothie doing in our hallowed acting and ent. tribe?)
(Oh, I used to be the director of a small singing group. I work in booths to make a living, and I'm looking to transition back into performing when I can afford to, and when I can find like-minded musicians.)

My two pesos.

with regards to booth/actor interaction...

I know I am much more inclined to both shop at, and refer customers to, booths where the keepers are involved. That doesn't mean they have to know me by name, do a gig with me, or anything else beyond be "glad" to see me in their booth.

It does mean those keepers, whether proprietors or sales staff, who sit in a corner, say nothing when I enter their space, offer no suggestions, ignore me or maintain their distance... probably won't see me again.

Those that greet me, discuss their wares, or offer their apologies when busy, and a pledge to assist as soone as they're done with their current customer... those are the ones I fequent, those are the ones to whom I direct customers.

Not an acting comment, just my 2p of observation.