Lego Mask Free Printable - Two Sizes - Lego party con Imprimibles (Lego Party Printables) - This site needs translation, but still usable. I also like the mini Lego bags that can be used as belt loops.
For class word wall: A couple white sheets, a note sent home instructing mom to dress the kids in colorful clothes, and a ladder (and a photographer who is not afraid of heights! So fun! You could also do shapes.or spell out the name of the school!