Do I really need to not eat anything at all before my colonoscopy, or are a few bites of jell-o okay?

Stay hydrated. Stay hydrated and follow the instructions given to you by your doctor. Failing to drink all of the prep solution and eating will lead to low quality colonoscopy.
Maybe. To be safe ask your endoscopist and /or the anesthesiologist if one is involved in your procedure. But ask days before your procedure to be sure you don't jeopardize their ability to perform the test or the quality of the test.Dont ask on the morning of the procedure!