They are all ridiculously hot. Hard to pick just 1, but I think over all I would go with Honoka. She just has the right combination of cuteness, beauty, and sexiness.
Marie Rose has the highest overall level of cuteness/adorableness, but she just looks way too loli to win in the beauty or sexiness category.
Helena Douglas scores very high in the graceful/elegant beauty category, but just looks too mature to win in a cuteness/adorableness contest.
Many other girls have different levels of cuteness, hotness, coolness, sexiness, beauty, etc... Honoka wouldn't win in any one category, but might just have the overall score for all categories.
Also does Mai Shiranui really count as a DoA girl or just a guest star in the game? She was first in the Fatal Fury games than in King of Fighters. Is King of Fighters still a thing or are they no longer making that series and Mai is now officially a member of DoA?