Jelks again
There's a character named Hannah Jelkes, with two e's, in The Night of the Iguana. She's a sympathetic character.
Could Jelks in Rectify be some kind of a nod to her, in the name?
There was a Breton king with that name with a variant spelling. He was made a saint. Late 500s - mid 600s.
Surname dot come gives other variants - Jekyll, for example. @ 2,100 with the last name Jelks in the USA, more common abroad.
William Jelks, early 2th century Alabama governor. Racist as all get-out.
Vaughn Tyree Jelks, actor b, mid 1970s, from Wisconsin.
So, not such an uncommon name, if you take into account the variants.
Love the name!