Thanks everyone!!

I love all three names, but probably Owen the best, but DH isn't so keen on it and he likes Callum the most. We have Callum on our list since we were pg with DD. Though when DS was born he just wasn't a Callum, lol! The thing with Callum is I don't like Cal as a nickname. With Owen, there's not really anyway to shorten it. It's just Owen. Plus I like the whole name, Owen Matthew. Matthen is my one of my brothers names and it's unlikely he will have his own children so I wanted to do this small thing for him by using his name. Though he'd never say it, he would absolutely love that I used his name. But I don't think Matthew goes with Callum....
Hmm, me thinks I need to work on DH!