Currently, Combee only has 2 abilities, Honey Gather and Hustle, meaning there is potential for a third ability. With 30/42/42 'bulk', even an Eviolite Combee won't be tanking much before going down. It also unfortunately lacks a redirection move and a healing move, making Clefairy generally the better choice. However, Combee does have far more effective speed control, at least outside Trick Room, with Tailwind/String Shot. It also has Endeavour, which could pair well with its solid base 70 speed, outspeeding 252 Base 110s with no investment.

Suggested Set:

Combee @ Eviolite
Ability: Friend Guard
Level: 50
EVs: 236 HP / 228 Def / 4 SpA / 4 SpD / 36 Spe
Bold Nature
IVs: 0 Atk
- Tailwind / String Shot - Endeavor
- Struggle Bug / Bug Buzz - Mud-Slap / Bug Buzz

36 Speed is sufficient to outspeed 252 Base 120 Pokemon under Tailwind or with String Shot. 236 HP and 228 Def gives significant physical bulk, while 4 SpA and 4 SpDef are enough to increase those stats by 1.

Combee could potentially also receive a number of additional moves, eg. U Turn, Follow Me, Rage Powder, After You, Aromatherapy, Protect, Roost, Air Slash, Encore, Infestation, Quiver Dance, Quick Attack, First Impression, Strength Sap, Ally Switch, Charm, Grassy Terrain, Nature Power, Natural Gift, Pluck, Purify, Rototiller, Simple Beam, Wide Guard and maybe Jungle Healing or Heal Pulse.

Potential Sets:

Combee @ Eviolite
Ability: Friend Guard
Level: 50
EVs: 236 HP / 228 Def / 4 SpA / 4 SpD / 36 Spe
Bold Nature
IVs: 0 Atk
- Tailwind / String Shot - Follow Me / Rage Powder / Wide Guard - After You / Struggle Bug / Quick Attack - Encore / Roost / Strength Sap

Same EVs as above

Combee @ Eviolite / Focus Sash Ability: Friend Guard
Level: 50
EVs: 188 HP / 4 Atk / 132 Def / 4 SpD / 180 Spe
Impish Nature
- Tailwind
- U Turn - First Impression / Follow Me / Encore - After You / Encore / Follow Me

180 Spe is sufficient to outspeed Base 143 Zeraora and 142 Dragapult. The other EVs are for physical bulk, with negligible investment for 1s in Atk and SpDef.

Any thoughts on the theoretical viability of Friend Guard Combee?