I can't speak for folks north of the 25th parallel but here in Florida a "slab on grade" will still have a footer poured as part of the slab. They ring the slab with a 12" x 8" "bell" footer. This has 2 #5 rebar in it. That gets tied to the dowel rods in the block cores you see in the top picture.
They put VisQueen under the slab portion but not under the footer portion.
As for the pool, you MUST attach to the pool steel. If you don't have steel or the steel is epoxy encapsulated 2005 code requires you to duplicate the steel with a 12x12 copper mesh. I think the same principle applies to footer steel.
