Conall - nice. I'd pair it with a mn that starts in a vowel sound if possible though because its so easy to loose the "LL's" otherwise. Eg.
Conall Nathan. Say that out loud compared to
Conall Aaron =)
Conri - I'm just not a fan of guys names ending with the "ee" sound.
Sullivan - I like it. Reminds me of the big cuddly monster from Monsters Inc.