If they're going to be shared with dogs,I'd suggest a rice based flour or potato flour.These are much easier to digest than regular or whole wheat flour,which are quite unhealthy for dogs
Similar flours(with no corn or wheat or spelt which is related to wheat and just as risky for causing allergic reactions in dogs which are extremely common)would generally be fine as well,with the ingredients in mind for hamster and dog safety of course!
As for peanut butter being suitable for diabetes prone animals,it's perfectly fine under the condition of it being all natural(as it should be regardless)and free of added sugars.Definitely no artificial sweeteners(extremely unhealthy,and some are even toxic)or unnecessary additives either,you want something simple and pure
You could chop plain nuts and add them into the biscuit mix for added flavor or certain seeds.If you wanted to try mealworms,crickets,freshwater shrimp,or freeze dried hamster safe meats those should work as well,or if you just want the protein boost out of it you may be able to find pure ground mealworms or crickets at a health food store and use that instead(unless you'd be willing to grind it yourself).