This may be the easiest, best, Fighter Formation in the game at present.
Ulrik, Sanguine, Zephyr, Barbie, and Seo-Yun.
These Heroes are fairly easy to get, and do not require to place high in events, or win one of the lottery type games.
Both Noct and Hanyu Ichiro is a good alternative to using Barbie since they both boost Fighters, although Noct is easier to get, while Hanyu is much harder to get, and requires winning one of the lottery games.
Because Hanyu is a 5 star hero, he can be evolved to a red star, meaning ultimately he can be much stronger than Noct. However, Noct is a very good replacement until you are capable of getting Hanyu, and can be maxxed at level 130 +5.
Importance of Hunt Formation
When you take your troops out hunting either Zombies or Zombie lairs having a good formation with Heroes that match your strongest troops, and the troops that you are dedicating your gear bonuses to, is an important step in maximizing your damage overall.
It is also effective in the Pit, and raids on player sanctuaries. You should always upgrade your troops to the maximum tier that is available based on your HQ level. This will allow you to use your might to its maximum potential.