Other Options
-Powder -Gimmicky to no end, but on a Choiced Opponent with a Fire move, or a well predicted Fire move can easily cause some damage and force a switch.
-Aromatherapy -Cleric moves are rare -almost every user should have this as an OO. That being said, waking up a Hypnosis/Sleep Powder/Spore victim, curing Toxic from a Tank, Burns from a physical sweeper and/or paralysis from a speedster always has value.
Looking over Vivillon, it is really quite pathetic. 80/50/50 bulk means that it dies quickly, and 90 SATK is its best offense. 89 SPD is fast for Alola... but Vivillon is not Alola native (though you can find Ocean Patterned Vivillon in Hawaii), so it comes in with a LOT of faster threats. Vivillon admittedly is possibly one of the best abusers of Compoundeyes, firing off accurate Sleep Powders and Hurricanes without a thought, but struggles to make use of it in higher usage tiers. Vivillon greatly appreciates Rapid Spin/Defog users, as losing half your health on the switch is horrific. And anti Rock support in general. Yes it has Energy Ball, but loses out on a precious move to make room for it. Anti Electric support is appreciated as well, as any speedy Electric type can come in and OHKO Vivillon once Sleep Clause is activated.
Countering Vivillon
Mow Rotom is Vivillon's nemesis, immune to sleep powder, neutral from Hurricane and capable of OHKOing with a STAB electric move... along with Stealth Rocks, Accelrock, Rock Slide, Stone Edge. Yeah. Vivillon hates Rock moves, especially given how prolific they are. Lycanroc, Aerodactyl, and Archeops all reliably outspeed an OHKO. Minior is another thorn in Vivillons side, immune to Sleep Powder when its shields are up and able to outspeed when its Shields are down, enabling to get Vivillon coming and going. RestTalk users are also dangerous, as Sleep Powder only slightly inconveniences them, and they can still strike back. Ice Shard users like Lapras, Mamoswine, Sneasel, etc. can reliably strike the butterfly down even after setup, though taking a boosted Hurricane is not recommended.