In my opinion, there is only one choice for a Flareons moveset and stats. The only logical choce is to make Flareon a mixed sweeper, giving her a special atack nature and full boost her in Attack and Special Attack. Here is the nature, stats and other details to the Flaeron that I use.
Flareon: Female- lvl 100
IV's: 29-hp, 30-atk, 25-def, 30-spa, 31-spd, 23- spe
EV's: 252-atk, 252-spa, 6-spd
Shadow Ball/Bite: I vary between these moves, depending on what is actually necessary. On the Shadow Ball side, it is a good special move, good for Ghost and Psychic types.However, Bite is also good on Psychic and Ghost types. Although, Bite is slightly weaker, but also has the likelihood of making the opponent flinch. I usually go with Bite, just so that she can exploit her high attack.
Hidden Power (Grass): Good for all of her weaknesses, rock, ground, and water. Good especially since unlike other fire types, she can't learn solarbeam
Flamethrower: STAB, type diversity against Bug, Grass, Ice, and Steel types. I think its essential.
Dig/Iron Tail: I actuall vary between these moves. I think I should just keep Dig, for Rock, Steel, Poison, Electric, and Fire types. However, Itron Tail has better power, if by a slight margin, and it can hit on the turn it is used, unlike DIg, which attacks the next turn.