My toothless wonder is Cal, who has only her four canines. She gets regular kibble with water. I don't wait for it to soften, although given the mechanics of feeding 9 dogs, it usually does sit for a couple of minutes or so. She's on a restricted diet at the moment, so her treats consist of a few pieces of dry kibble.
Edie also has very few teeth left--certainly not enough to grind up kibble--and she gets the same.
When I was feeding different treats to Cal, I used one of the rolls--Natural Balance or Rollover.