I live on Guanaja since many years, and I can assure you that this island is one of the safest places you can travel to. Most of the times I don't even lock my door, and I always sleep with my doors open. There might be some opportunity theft like anywhere else in the world. But even that would only happen if you leave valuable things in very tempting places.
Roatan I also understand is very safe. Even though there are parts of town where you shouldn't be alone at night (like anywhere else in the world).
All in all the Bay Islands of Honduras are very safe, and have nothing to do with the bad reputation the Honduran mainland has.
Best regards from Guanaja :)