Delawares DO breed true. I have never heard that they don't.
Remember with mine - they are a project and will likely take a while to get to "perfection!" 5 generations when starting from scratch? Well, I dunno about that. Assuming correct breeding? Well, I am no expert - merely a novice.
All of my project chicks (since F2) have hatched out yellow. Plain yellow and nothing else. I have never had the "greyish fluff down both sides of its body," that you mentioned. I wonder how it will turn out. I am anxious to hear!
My first broody of the year is one of my Delaware girls. She is setting on New Hampshire eggs (because they were the only pure eggs I had).
I have some medical issues to tend to, but if all works out (I hope to find out next week), I would like to pen and hatch some of my Delawares before summer has come and gone. I hope you all keep hatching and sharing and keep this line going!
I am sending my New Hampshires to Nebraska, to decrease my population and work load. I will just keep my Delawares and Barred Rocks (and a few miscellaneous layers). I don't think I will be keeping alot.