But if it's for kids and therefore the answers are easy and general about Pokémon, why bring the Threehouse folks?
To be fair, what questions would kids ask that would be hard to any adult to answer. I remember a kid asking if Pokemon X will work on the 2DS way back in the day to a rep at a convention. So in most cases, we might see kids talking to them or asking them mostly about Let's Go, especially if parents will be present. We have to remember, the GO community is big too, and attracts families of younger patron's, as did Let's Go.
Though it does seem a bit odd that they'd have the Treehouse reps called over just to do an event to entertain young children, but then again times have changed. I still remember the Pokemon tours they would do (and the only means to do Pokemon Events as well) and they'd hire locals to dress up as NPC's from the games to entertain kids, and even hand out TCG packs. I presume it will be similar to that with only then not needing to go out and hire random people this time (as a safe measure especially after what has been going on as of late).
In all, I'm going to temper my expectations for anything Pokemon Gen 8. Will we hear anything this month, maybe, I'm not sure. But I think I'm heading to Team May/Team E3 after Pokemon Day (I still remember the fiasco of last year lol) if we won't hear anything then.