I knew a Seamus in high school. He was a star swimmer and had a lot of friends and as far as I know, he never got made fun of when I knew him in high school. Now, if he weren't so "popular," I do wonder if he still would've been spared from name-teasing. I am an elementary school teacher and I definitely see the potential for teasing at least when a Seamus is that age. If you're a strong person/personality, then your kid probably will be too and so maybe that won't be something that bothers either of you.
It's a shame Sean is off the table! I love this name and it's familiar so people know how to pronounce it correctly.
I have heard of One Direction being an elementary school teacher, but had no idea of their names so I don't think Niall is something to worry about. I also have always loved the name Patrick, but I knew two guys growing up with the name and both were called Pat, which I personally loathe, so I'd only use it for a middle name. I really like Brendan. Yes, it feels a little 90's, but so could Sean and Patrick and they're still both fabulous names. I can see with Brendan being close to trendy Braden and Brennan that it could be a concern, but I still think it's known enough to be recognized as NOT being lumped with those type of names.
Neal/Neil (instead of Niall)
This is so difficult because a lot of these names (or very similar names) are either already used by our family/friends or have other connections that would turn us off from using them.
Reilly - We know a female Rylee; love her, but wouldn't name a son after her. Plus, it kind of brings to mind Bill O'Reilly...my parents would like that, but my husband...not so much!
Brody - A friend/co-worker of mine has a bulldog named Brody. All the students know about him, too, he's like the class mascot.
Eamon - Our friends just had a baby boy named K@em0n. I'm not sure it goes with our other names anyway.
Ian/Owen - My husband does actually like one of these, but I can't remember which one! He says the other one is "too Scottish". Owen is my aunt's maiden name, though, so we probably wouldn't use it for that reason.
Lorcan - I like that it can be Anglicized as Laurence because that's my father-in-law's name. I think it sounds very different than our other names, though. Not sure how I feel about it.
Ronan - I think it's cute, but my husband doesn't like it. Too much like Conan...I guess.
@Chrisco, My husband doesn't care for Declan or Liam, either! I associate Declan with Southern USA more than Ireland anyway, so I probably wouldn't use it. But, I don't understand why he wouldn't like Liam. William is a family name in his family.
I'm pleasantly surprised to see so much support for Seamus, though! I have always really liked it.
Aidan is authentically Irish and I'm fond of it, but Nameberry generally considers it too popular. I only like this spelling.
Alan is authentically Irish, but, on the opposite end of the cool scale, generally panned for being old-man-ish.
Shane - Not particularly authentic and kind of cowboy-ish but I like it. I find it more endearing than Sean, probably because it's never been as popular.
Eoin - which is just a very-Irish-indeed way to spell Owen. My DH has been wanting to use this.
Malachy - I love this one, but I can't use it because my married surname is one of those 3-syllable Irish names that starts with M and ends with y and it's too same-y.
Barnaby - Have an Irish friend who adores this one, not sure I'd be brave enough to use it.