I had a popular name for my generation so it's not that easy for me to just go with a name I love if it's gaining too much popularity. I HATE having a popular name and I don't want my children to have to deal with it. Not to mention, in high school, I was almost beat up by a girl who thought I was the Stephanie who wrote her little sister a nasty note!
Honestly, if you really love one of those names, go for it! I grew up with a very popular name, but I knew more boys named Aaron then girls. lol
If you really love a name and can't find anything else you love just as much, go ahead and use it regardless of popularity. It's not a big deal. I'm an Emily, and I had a class with another Emily maybe five times my entire school career. Never bothered me.
Declan doesn't really need a nickname...I'd keep it. Also, Cashel (Celtic castle or fortress), Bastian, or Silas.
I totally get what you are saying. I grew up with a popular name, and hated never being the only "Rachel" anywhere that I went. So I made sure that my own daughter had a more uncommon, although still recognizable name. For my boys, I chose relatively more popular names. One has been in the top 20 since 1983 (still there) and the other was my attempt to be more distinctive (it was hovering around #30 the years that my sons were being born.) Since that time, my more "distinctive" name choice has shot up to the national top 5, and my older son's name has decreased in popularity standing (still not what anyone would call uncommon by any stretch.) So you never know what will happen to the popularity of the names that you like. I also really think that a name's popularity means so much more for girls than boys. Both of my sons like having top 20 names, and I even went through the state standings with my younger son and he was THRILLED when we found out that his name was #1 in New Mexico! (not where we live) My advice would be to try to chose a name that you and your husband LOVE so that you won't be sad no matter what happens to the popularity standings. I'm currently trying to name my fourth son and luckily the name that I love is still out of the top 100 but since it has been suggested twice in this thread alone, I'm pretty sure that it won't be so uncommon for so long. Will I be disappointed when/ if that happpens? Yeah, a little bit. But I LOVE the name so much that I will still LOVE it even if it gets to be top 20 in a couple of years.