Well, Pokemon wise, for S.O.S chaining you want tanky Pokemon, so bring Pokemon like snorlax, Trevenant, Toxapex, Zygarde(At least 50% Form!), Machamp,and Muk. For moves use ones that boost defensive stats, like Amnesia, Curse, Bulk Up, etc. Heal Pulse might actually be a good option if Bagon gets low on health. Rest is a good option if your Pokemon get low on health. For items obviously bring adrenaline orbs to lure out S.O.S help. If you have finished the alolan pokedex definitely bring the Shiny Charm. Good Luck!