I dont necessarily have a vote, because I cannot tell you whether people will look it up or not. I mean, for example you never know, your daughter may look it up one day, i know i have looked up the meaning of my name. There are several irish names that start with the letter K (i am irish myself), now the harder to find names will be Gaelic names that start with a K. so, are you looking for actual Irish or Gaelic names?
Honestly, i never knew Kyra meant 'the dark one,' but when i first read this, i was just overviewing it, not reading the whole thing, and when i thought about the dark one, i wasn't thinking dark as in skin-color, i was more thinking along the lines of light and dark, good and evil.. type thing.
Anyway, ultimately you are the one who will decide her name. But again, there are several K irish names.. here are a few, not trying to persuade you, but just thinking of a few off the top of my head (i was looking into K names before i knew what i was having w/ my last baby, lol)... Kacie, Katelyn, Keely, Kenna, Kelly, Kennedy, Kerrin, Kerry, Kevina, Kiely... im sure there are many more than that, but those were some that i could think of.. again, this truly is your choice