Would these 5/8" Diamond Soft Tiles work as a temporary grass covering to create a floor for a backyard event? Would it support tables & chairs and people walking over it on top of grass?

These tiles wouldn't be recommended for use on top of grass. Standing on top of the tile with a soft surface like grass beneath might unlock the tiles from each other. Rolled products like our gym floor covers or even our Dance Flooring is a great option for outdoor events.