Hau (Route 3): Cutiefly can outdamage Pikachu with Silver Wind, 3HKOing it; the move also does well against Popplio, scoring an average 3-4HKO. However, it loses against Rowlet and Litten, due to Peck and Ember respectively; they can only be beaten if a prior use of Silver Wind has caused Cutiefly's stats to receive a boost.
Hala (Iki Town, Fighting-type): Cutiefly's double Fighting resistance is very useful against Hala. Mankey can be 2-3HKOed by Fairy Wind or 2HKOed by Draining Kiss, if Cutiefly already knows the move; Makuhita is 3HKOed by both. Fairy Wind 3HKOs Crabrawler while Draining Kiss has high chances of 2HKOing; in case of repeated Leers, it is advised to either heal or use an X Defend instead of switching, since Crabrawler's critical Pursuit on the switch can chip away a significant portion of Cutiefly's health from -2 Defense or below.
Ilima (Hau'oli City, Normal-type, optional): Gumshoos can destroy Cutiefly even with regular Tackle, OHKOing on the spot; Smeargle also beats Cutiefly with Ember, scoring an average 2-3HKO.
Hau (Paniola Town): Although Cutiefly's Silver Wind is still slightly stronger than Pikachu's Electro Ball, Pikachu will outspeed due to the Speed EVs, making Cutiefly lose the battle unless Silver Wind gives it a stat boost by the second turn; even so, in low health, Cutiefly can be finished off by Quick Attack. Light Screen can, however, help Cutiefly win against Pikachu. Even with screen moves, though, Cutiefly falls short against all three of Hau's possible starters, being outdamaged even by Brionne's Aqua Jet.
Gladion (Route 5): Cutiefly gets destroyed by Zubat's Wing Attack. It may attempt to use Stun Spore against Type: Null and whittle it down with Draining Kiss or Silver Wind, though the effectiveness of this tactic entirely depends on the turns that the enemy stays fully paralysed; even with Reflect up, Type: Null's Tackle still outdamages Cutiefly's Silver Wind.
Totem Wishiwashi (Brooklet Hill): Bad for Cutiefly. Wishiwashi's Water Gun is a 2HKO even without the rain, and Draining Kiss can barely scratch the Totem. At best, Cutiefly can either use Stun Spore or Struggle Bug on the first turn, lessening the offensive power of the enemy before switching out.
Battle Royal (Royal Park): Cutiefly is not safe here. Rockruff's Rock Throw and Type: Null's Tackle combined can off it from full health, and Torracat's Fire Fang can even OHKO.
Totem Salazzle (Wela Volcano Park): No. Even an already evolved Ribombee would stand no chance against Salazzle's Flame Burst.
Totem Lurantis (Lush Jungle): Cutiefly is insufficient for this battle; even though its Silver Wind is a 3HKO against the Totem, which can only KO in three turns or more even with Solar Blade, the possible allies Trumbeak and Castform both represent a danger with their Pluck, Rock Blast and Sunny Day + Weather Ball moves. Ribombee has much better chances, nearly OHKOing Lurantis with Pollen Puff, as well as being capable of surviving one of Castform's hits easily.
Plumeria (Akala Outskirts): Ribombee is at a great disadvantage against both Golbat and Salandit, and should not be used.
Olivia (Ruins of Life, Rock-type): No amount of help can make Ribombee useful in this battle; even Reflect is far from enough to shield it from the Rock moves all of Olivia's Pokémon have. Ribombee should never be used in this battle.
Lana (Konikoni City, Water-type, optional): Pollen Puff 2HKOs Chinchou and Shellder. Ribombee needs to put up Light Screen and be over half health by the time Araquanid is called into battle; its Hydro Vortex can nearly OHKO Ribombee otherwise, and Acrobatics is at best a 3HKO. Light Screen must be maintained at all times, since even regular Bubble Beam can 2HKO without it.
Kiawe (Royal Avenue, Fire-type, optional, Sun only): No. Ribombee is at a serious disadvantage against even the weakest of his Pokémon. It may only manage to beat Fletchinder by spamming Acrobatics.
Mallow (Lush Jungle, Grass-type, optional, Moon only): Acrobatics 2HKOs Phantump and 3HKOs Shiinotic. Steenee is OHKOed by Pollen Puff.
Nihilego (Aether Paradise): No. Even Light Screen can barely make Venoshock a 2HKO, and none of Ribombee's moves can do any better.
Hau (Malie City): Ribombee is not fit to fight against Raichu, Flareon or Torracat; Raichu's Psychic 2HKOs and Ribombee is highly unlikely to outspeed, and even the best of its moves (Bug Buzz or Pollen Puff) is highly unlikely to OHKO, while the Fire-types can kill with Fire Fang and Z-powered Fire Fang respectively. It is also unlikely to win against Dartrix; while Reflect is sufficient to outdamage its Pluck, it takes a turn to set up, and since both Bug Buzz/Pollen Puff and Reflect-shielded Pluck are 3HKOs, Ribombee would still be on the losing end without any healing. Ribombee has an easy victory only against Leafeon, with its Bug STAB of choice; it can defeat Vaporeon or Brionne too, but needs to be backed by Light Screen at all times, to avoid their Water moves outdamaging its own STAB.
Cutiefly's earliest possible moveset is made of just Absorb, Fairy Wind and Stun Spore. Bug STAB comes soon afterwards at level 10, through Struggle Bug, and a later upgrade in the form of Silver Wind as early as level 13. This makes Cutiefly a great early game Pokémon, having good coverage and high base power moves at its earliest levels; Draining Kiss, at level 16, powers up Fairy Wind as well. Cutiefly then learns the fairly useless Sweet Scent at level 21, and gets a further Bug upgrade upon evolution: Pollen Puff, a nearly broken base-90 power move that can be obtained as early as level 25. This makes Bug Buzz fairly unnecessary at level 28, though the move does have an added Special Defense lowering chance that Pollen Puff is lacking, so it should be preferred. The Fairy upgrade comes around again at level 35, and it is Dazzling Gleam. At this point, Ribombee will have its best offensive tricks. Aromatherapy at level 42 will generally prove useless, due to the line's low bulk and the existence of healing items; the last and absolute best move Ribombee can learn comes at level 49, Quiver Dance, which makes Ribombee a powerful special sweeper if its frail defenses are properly managed.
Ribombee's movepool by level up is excellent, and tends to overshadow its own TM options. Acrobatics is a noteworthy move in the early game, and is powerful enough until Cutiefly evolves; U-turn is not very strong off Ribombee's low Attack, but makes it a better lead, which can switch out of battle safely - due to its remarkably high Speed - leaving chip damage on its trail. Good special options are limited to Psychic and Energy Ball alone, since Dazzling Gleam is available to Ribombee by level before the TM is accessible in the game, and even Calm Mind is obtainable fairly late, making it only a temporary Quiver Dance replacement until Ribombee hits the long awaited level 49. Defensively, Ribombee can run both Reflect and Light Screen, though Reflect will generally be more useful for setups, since Light Screen is also outclassed by Quiver Dance for Ribombee that do not play a support role.
The earliest available Z-move that is good on Ribombee is Savage Spin-Out, excellent against any Pokémon that does not resist Bug moves. Twinkle Tackle is a late game Z-move, but nevertheless available just early enough to help Ribombee curb Hala's League team with ease. Bloom Doom and Shattered Psyche are other good options, though Ribombee is unlikely to make much use of the latter, since Psychic coverage is largely redundant with its Fairy STAB.