Re: selling testers?
I don't see why you couldn't mention whose tester it was. I actually have a few testers in my stash that were not originally tested/owned by me. It is imperative that you mention that it was a tester. I actually purchased a Luxe on ebay that was a tester and not mentioned at the time. Boy was I ticked. It's still a wonderful diaper, but it isn't worth as much because it is a tester.
It is also bad diaper karma to sell something for more than you paid for it. Granted if you tested for someone who has become hyena, then you could probably get more than you paid. But, keep that in mind as you go to sell - pass the good joojoo along.