After completing Lana's Island Trial, the Sudowoodos will let you go south to Route 6.
To the left, you can battle Dancing Family Jen and Fumiko. They have a level 16 Igglybuff and a level 17 Jigglypuff. You get 872 Pokédollars for winning.
Southwest of the Dancing Family, you can find a Revive.
Farther south, there is a Pokémon Breeder in the grass. Pokémon Breeder William has a level 17 Bounsweet and a level 17 Mareep. You get 680 Pokédollars for winning.
If you go through the grass behind William, you find a side-entrance into Paniola Town. Check on the hay bales to the north to find a hidden Super Repel. Down below, there is TM88 Sleep Talk.
Back in Route 6, go south and you will find Hapu being harassed by the Team Skull Grunts who have been bothering you. You will battle a Team Skull Grunt who has a level 17 Drowzee. You get 544 Pokédollars for winning.
Afterward, Hapu encourages you to visit the Battle Royal Dome, you can go east into Royal Avenue, or you can finish exploring Route 6, which leads to Heahea City to the south.
If you go south in Route 6, you can battle Beauty Brittney, who has a level 17 Cubone. You get 544 Pokédollars for winning.
If you go west from the Beauty, you can use your Tauros to break the rocks and get a Rare Candy.
There is some grass south of the rocks. To the left of the grass, you can find a hidden Carbos.
Go back to the main path. There is a Dancer east of the path where you found the Rare Candy and Carbos. Dancer Maika has a level 17 Oricorio. You get 680 Pokédollars for winning.
In the grass east of Dancer Maika, there is a hidden X Speed.
Eastern Heahea City
If you keep going south, you will reach the eastern part of Heahea City, which you couldn't reach before because a guy on a Stoutland was blocking it.
While you are here, you can visit the Dimensional Research Lab, although you can't do anything in the lab right now. To the right of the Dimensional Research Lab building, there is a narrow path that leads to a Big Mushroom.
To the left of the Dimensional Research Lab, there is an office building. The Game Freak office is on the second floor. Talk to the girl in the upper-left of the Game Freak office to get a Lemonade. You can get Fresh Water from the vending machine.
Go to the third floor and enter the office there. Talk to the girl behind the counter. You can agree to help look for the pokémon who won't leave its box ever since its trainer passed away. You will get the Left Poké Ball. Talk to her again and she says that the trainer who passed away was on Ulaula Island.
South of that office building, you will find Diglett's Tunnel. If you go in, you find Olivia talking to a couple of Aether Foundation people. But you can't go farther into the tunnel yet. You can encounter wild pokémon there, though.
For now, go north through Route 6 to reach Royal Avenue to the east.