Now that I think on it...
It’s a bit of a wasted opportunity that our two main storyline, past-Gen cameos, Colress and Grimsley, didn’t get much relevance to the plot aside from giving you a TM/Genesect Drives and the Sharpedo Ride respectively.
It would be cool if they were investigating Team Skull/Aether Foundation alongside Officer/Kahuna Nanu. It’s very vaguely hinted that Nanu doesn’t trust the Aether Foundation. Acerola brings up he could get them to help him out and protect the local Pokemon, but he doesn’t, opting to do it himself. Now, Nanu is apparently kind of a lazy guy–he lets Team Skull run amok, didn’t even want to be Kahuna, and outright refused to be a member of the E4. So, why would he pass up the opportunity to let someone do the majority of the hard work? Maybe he picked up on something.
Like, perhaps Nanu contacted the global police to help him investigate and he was able to pull a few strings, so they sent him a member of the Unova E4 and Colress (who had been arrested in between his trip to Kalos and here, but was able to strike a bargain to avoid jail if he helped Grimsley and Nanu investigate–a “lazy” police officer with a dark past, a gambling addict, and a
mad scientist ….together, they fight crime!) Unova and Alola are both Pokemerica, so theoretically may be close by. And I can imagine that both could be of use when it comes to dealing with the Ultra Beasts, Grimsley being a strong battler and Colress being a scientist.