I love Liam, Lachlan and Cullen. I actually really like Cullen, I don't think its too strongly linked to Twilight at all.
I love Deacon. I don't see the problem with having a religious association to a name...unless you're atheist. A lot of names come from the Bible and people rarely even think of it.
After reading your explanations I vote for Liam or Lachlan