Dylan is the best of the three. I prefer it as a feminine name.
Dana is the most unisex, but the one I dislike the most. Too short, yet has 3 pronunciation options in 4 letters. So confusing!
Dallas is all masculine. The association with the city and the TV series makes it unusable in my opinion.
Others to consider:
Dale,
Darcy,
Daryl,
Delaney.