Yes!!
I would be more concerned with how people would pronounce with that spelling. Killian is fine!
@Linda my son is three years old and it’s a traditional Irish name. I’m not worried about his name I’m pregnant with a girl and wondering if naming my daughter Collins would be too similar to my son’s name Cillian.
I still say go for it! They sound cute together!
They cute together might be a lot of C’s and L’s to write out but Don’t sound too similar when pronounced if you love it use it.
Girl if you like it go for it! Me personally really love it and love how similar they are. Like I have a Maddox right now and if I have a girl her names gonna be Madelyn and people are telling me they are too much alike but I absolutely adore it and that's what I wanted anyways. 😁 Do it if your absolutely in love with it!! 🥰❤️