For Deiseach, especially,
because I know how much this will mean to you - a little window into the American mind. (I Did Not say "twee." I didn't say it, dammit! --I also didn't suggest forwarding this to all your friends and relatives just for kicks, either. These are not the droids you're looking for...)
And yes, there is a Nora Roberts book on the dollar table called "Irish Heart," which I haven't read yet, and there is apparently also in the Robertsverse an, enquote, "evil Celtic god"
whose name is Kane. His nemeses on the side of Good are the Celtic god and goddess Pitte and Rowena, and no, these aren't supposed to be their modern "cover" names. I guess I must have slept through that part of our Celtic Mythology section in the Medieval Lit course I took.
But even that pales, besides the fascinating, fabulous, Roarke who is the hubby of Detective Eve Dallas (and no, I'm not the first to call her a flaming Mary-Sue!) who just happens to be a) a gorgeous roguish sexy dark Irish b) billionaire who owns most of futuristic-NYC and pretty much any industry that would be useful to the plot, eat your heart out Nancy Drew!, c) who also grew up a dirt-poor, abused and neglected child on the mean streets of Dublin and ran with gangs before somehow getting his act together and becoming the most desired, desirable man in the whole wide world.
The thing is, Mythic Celts are so much less messy and inconveniently ambiguous and, well, modern with all that modernity entails of dingy mundane pragmatic problems like paying the rent than real life Irish or Scots citizens - unless you can magically create a Tragic Plebian Background for your Handsome Prince out of it, which doesn't involve an incomprehensible accent, uncouth phrasing, an education with serious gaps in it, and a perpetual grinding resentment against the Old Money who were able to go to University etc along with problematic taste both in terms of not being able to tell "classy" from "really expensive yet tacky" and likewise thinking that "what, cheap beer and crisps is a GREAT meal" kind of thing...