Ceilidh is the Scottish Gaelic spelling, Céilí is the Irish spelling. Ceilidh is pronounced a little differently. I'm not an expert on Scottish Gaelic, but I've heard it said more sort of like /kay-lay/.
Because I'm an uptight purist, I wouldn't use this as a name for the following reasons:
1. it's not a name, it's a vocabulary word. In
Ireland it's definitely not a name. It's even used as a word in the USA, to refer to Irish dance & music competitions in certain circles.
2. A kid in the USA named Céilí would probably get called Seeley 99% of the time when her name is read off a list. The time she would spend explaining the name would be long and involved-- it's more than just "
Katherine with a K"-- "cei" doesn't even make a "
Kay" sound in English, so she would have to spell it every time. I'm "
Norah with an H" which not everyone can handle for some reason and believe me, it gets old explaining it every single time I have to spell my name over the phone! (
Norah. With an H. No, N -O -R -A -H. [people have spelled it Nhora, Nohra & Norha each more than once!] When they read it off the list, I am always
Noah.)
3. The Irish language isn't pronounced like English. Though many of the sounds are similar, Céilí and
Kaylee are approximate equivalents, not homophones. Céilí sounds more like /KEH e'l ee/ but I really can't spell it out well.
Caoimhe is a nice name, but I'd use an anglicized form, like
Keavy or
Keeva. Ditto for
Aislinn. It looks pretty, but I'd probably spell it Ashlinn.