Olivia turned out to be easy. Crabrawler swept her with two Power-Up punches on Anorith and a +2 Brick Break on both Lileep and Lycanroc. Crabrawler was low enough on HP from Anorith that Lycanroc could have probably KO'd if it had used its Z-move (even if it would be not very effective) but it went for Bite instead for some reason. Oh well, a win's a win. After that, I took care of some story stuff at the Aether Paradise (including taking down an Ultra Beast and meeting a 40-year-old MILF) and now I'm officially on the third island to continue my adventure.
Also, something I forgot to mention before: At the beginning of the game, I did hack in a bunch of Everstones to put on my Pokemon so that I wouldn't constantly be asked to evolve them upon every level-up. They'll be holding these for most of the game, but for important battles (like island/grand trials) I might give them other held items. This is the only modification I've made in this save file, everything else is completely normal.
https://i.imgur.com/PmF1p9q.jpg