regarding to base atk stats and efficiency (227 atk and high hp pool) I'd go for Arc if it has a moveset like (fire fang-fire blast or bite-fireblast) It's a good mon.
Flareon is not bad either , I guess it has been buffed CP wise , it would not be a bad idea to power it up too. Its ATK is better than Arcanine's but its HP pool is not great as much as Arcanine's...
so good luck bro enjoy it