I imagine Dash to be steamlined, with a sort of small and slim body and a long “sloped” muzzle. She is an athlete who specializes in flying, so she’d have a lot of muscle mass in her chest and wings, while maybe be a lot weaker in her legs? She doesn’t “care about her appearence”, by which I mean she is very concerned about seeming cool and uncaring. So her mane and tail would be relatively short and styled to look messy.
Daring Doo would instead have less muscle mass, but spread out over her entire body since she got the muscles from traveling and adventuring. I tried to draw her stockier and more solid; her body is built to last during hard work, long days and possibly very little food, not to work in short bursts of amazing feats. Unlike Dash, she truly doesn’t care about her appearence, aside from it being comfortable, not in the way and easy to maintain. So her mane and tail is just cut semi-short by herself, clean and brushed.
Also she has white markings, because I like the way it looks