From what I can find, there’s no recorded cases of dog flu affecting rabbits. Rabbits should still be protected from direct contact with dogs that have flu as a safety-measure. In your case there wouldn’t be direct contact. I think your buns will be safe if you wash your hands and change your clothes after you’ve been in contact with the dogs. Dog flue doesn’t affect humans.
Most flus are species-specific, but there are examples when a flue has crossed the species-barrier, as was the case with the Spanish flu, the more modern bird flu(s) and the swine flu.

I agree, there isn’t any records of this happening. But it doesn’t hurt to wash your hands after having contact with the dogs.