Don't take this wrong but maybe look at the micro grow forum and see what has worked for other people.
The white surface will be fine, you really don't gain much from adding a relective foil.
Put the larger fan up top to draw air out, lose the smaller fans or use them inside the box to move the air. Lower holes can be passive intake.
Your using alot of fans with this build, why?
Just my 2¢ for what its worth