If the column isn't parallel to the couch, but further back, I don't think 7.1 would work too well for you.
Mounting on the ceiling might work if all the surrounds were mounted there, but you may get reflection issues from being that close, unless you went in-ceiling speakers. Hard to say without actually having the speaker up there. What receiver do you have? Might be more beneficial to go front height.
Don't believe everything on the Interwebz! A duck's quack DOES echo!