Oh my, where to start on those questions? How did you even get to the point of getting biopsies and such if you had no symptoms? Just curiosity on my part.
You could ask 20 different people about knowing when a flare is going to start and get 20 different answers. Most people usually start with something other than regular normal bowel movements. Blood and mucous in the stool, pain and cramps may be associated with the flare starting. A lot of people also have the added factor of MANY trips to the bathroom throughout the day when flaring. The constant trips to the bathroom then usually lead to weight loss.