Don't use luan if your going to use a self stick tile. Luan is made with a mahogany layer that is very oily. Glue doesn't stick well to it. Use 1/4" plywood. just plain old plywood not luan.
You question in what is needed besides a sub floor. A sub floor anything below the surface. If your going to lay tile ceramic, or other stone type you will need a cement sub floor. If you are going to lay linoleum or vinyl you should fill any gaps in the joints. If the seams are really tight you can get away without filling. But fill any imperfections like hammer marks, Screw indentations etc. As they will show through the vinyl in short time.