disclaimer: this is probably hogwash.
I was at the imdb page because I hadn't caught all the characters names (specifically Tim Roths!) and they struck my eye funny. Especially "Eli Loker". It looks like "Loki", which I thought was interesting given his characters penchant for "radical honesty".
Cal Lightman. What is Cal short for? Looked up "Callum" and it means "dove". Dove and a man of light. Sounds like a bringer of truth to me.
Gillian Foster: "Young Forest" Flexible, macrofocused? Naive? Earthy?
Ria Torres, Ria is short for Maria, which means "bitter sea" and Torres means a tower. Lighthouse, much? Shining the light of truth on the bitter rocks and keeping people safe.
Ron, Gillians's husband: Ronald means "advisor to the King", it'll be interesting to find out what his job is that supposedly keeps him late at work.
Again, my brain is probably making shit up, but I had to share. And of course, if we presume that Cal's full first name is Calvin, then the meaning changes to "Little Bald One".