It depends on a lot of factors, there may be bone fragments, even intact bones, but the point is that it doesn't take a crematorium method to reduce a body to ash. Funeral pyres are not crematoriums, and they do the job quite completely. When excavating burial mounds it's surprising how little bone is found in intact cremation urns. Now sometimes there are fragments, and some of any remaining bone may have been taken by people as remembrances, but funeral pyres do a complete job and they are open air using just wood. When you add an accelerant the whole thing burns at higher temps at an accelerated rate.
For example, we've all cooked over an open flame. How long does it take to cook a steak to well done? Now take that steak, put it in a trough, poor some gasoline on it and light it, how long before it's cooked to the same wellness?
Cookies are a different thing, since baking is different from roasting. When you cook meat in an oven, that's roasting. When you bake cookies, the process is different which is why it's so hard to bake cookies over an open fire without being wrapped in tinfoil. You can fry meat on a frying pan, but it's hard to get the same results when you put cookie dough on a frying pan. That's because meat is roasted, while cookies are baked. Roasting is taking a something that has a solid structure and cooking it, baking is taking something that has a liquid structure (cookie, cake, bread etc) and making it a solid structure. When you're cooking something with a liquid structure it requires a different method to make that change to a solid structure.
