What is the best way to get non permanent marker and pencil marks off a laminate table?
The best way is to use Windex and red microfiber cloth. You can use any color microfiber but red works best. Microfiber has little hooks at the end of the cloth that helps to remove marks then holds the residue until they can be wash. Be careful not to use dirty microfiber cloths on other surfaces.
What size chair(s) should I buy for my classroom?
Here is a chart that should help.
What is the difference between all the typical classroom stack chair?
Most of the "typical" classroom stack chairs are made out of polypropylene or polyethylene plastic. The difference between the two is mostly in the length of the plastic strands. Polypropylene chairs don't need a metal back support where polyethylene does. I would stay away from the chairs that have the rivets that hold the seat and back to the frame. The plastic cracks at the rivets causing skin and hair pinch points. Other than that, there really isn't that much of a difference between chair manufacturers so buy where you can get the best price and the best service.