Never pick Flareon. Atleast not without a good moveset, since - #112996443 added by edgeworthy at Eevee !
Pokémon of the Week - Flareon
What is the best nature for all eveelution? | Pokémon Amino
Flareon raid boss will have Last Resort moveset : TheSilphRoad
Got a perfect shiny Eevee after chaining 213. Now I have a perfect shiny Flareon! (Nature was perfect fit for Flareon) : PokemonLetsGo
GIVEAWAY STATUS: OPEN — Milestone Giveaway~ All Pokemon (except Eevee) are...
Jolteon. Naive is a speed boosting nature. The best natures are modest, adamant, jolly, and timid. Most eveelutions benefit from modest and timid, except for flareon and leafeon