I would also look at alternate spellings, as I have seen the name(s) here in Amite Co (next county) spelled McLean, McLain, McClain, McClaine, MacLean, etc.

Real Son Alcus Huff (now deceased) once told me of a war story of his father where he mentions a Will McClain from around Gloster picking his father up after losing his horse in a skirmish. John Huff was in the 11th/17th Ark Mtd Inf at that time, serving here in SW Mississippi.

May not be the same man, though.

Virgil