I prefer the spelling
Cameron, and I love the nn Cam/Cammie, for some reason. I don't see it as exclusively masculine, more as an established unisex name. And yes, I think
Kamryn's a bit trendy, but I can see why you might like it; it looks cute and more modern. I actually sort of like the meaning "crooked nose";maybe it's my quirky sense of humor, but it seems to denote character. Anyway, I think it goes well with Casey...I wouldn't worry too much about the name looking feminine, but that's just me.