Hi newyorkiemommy. Nothing better is there than that feeling of excitement and anxiouness awaiting a new pup? In your case, double that feeling as you are receiving 2 pups. How fun and thrilled for you.
Regarding grooming supplies. I found it handy with Schatzie to have a quality puppy shampoo (I use Vellus), conditioner (same brand), a slicker brush and a mustache or flea comb as their hair can be so thin the comb helps a lot!!
I don't like to let Schatzie air dry so I have a hair dryer I use on her. (low setting), yet you probably already have one of them.
There are non essential supplies like special silk oil's to make their coats shine, top knot bow gel, doggie perfume, etc.
I hope this helps you out a little and again welcome. Let us know when your adoption is final and post pictures of your new little ones.