Base on my countless testing.. NOTE: This is with OHK feature on
01. Jushiro - His number 1 and 3 skills are range. His #1 is the long range Wind Whirl and his Strong Attack #3 is the Wide Lightning Attack which is also range.
02. Kisuke (Candy Shop Owner) - His skill #1 is a sniper! 90% chance that he will use it right away when the battle starts. Install Kill there.
03. Sode No Shirayuki - Her basic attack is a long range but it seems like.. it's range is a lot larger/longer than average Range Attack Range.. Always put her on the MIDDLE..
There's 60-75% chance she can kill all 3 if shes on the middle (just in case your top and bottom dies first)
04. Nanao (Kido) - Her Kido sticks and Fire Kidos are (use her if you don't have some of the characters listed above)
05. Stark (I don't recommend him) but he has that sniper on #3 that can go a long way.