You cannot successfully install rebar in a concrete floor less than 4 inches thick. The problem is the lack of cover. ACI requires a minimum of 1-1/2 inches clear cover on top of the rebar, and 2 inches clear cover if the concrete touches soil. With a two inch thick slab, this is obviously impossible.
Should you install rebar or wire mesh, the anticipated result will be rusting of the rebar or mesh, with ensuing expansion of the metal, followed by cracking of the concrete.
You can install a 2 inch concrete floor without rebar, you may want to consider using fiber concrete to reduce cracking.
If you plan to continue to use the garage for vehicle storage, you would certainly want to rethink using bubble insulation. As previously noted, this would certainly compress, and possibly break, under normal garage type loading.