I think
Georgia is a nice name. If you like it and it honors your grandfather then I see no reason why you shouldn't use it. I can understand thinking
Georgia Lynn is plain but I don't think
Georgia Lynn Marie is any less plain.
Lynn and
Marie are equally plain as mns imo.
“It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.”
~Mark Twain