Could a sudden proliferation of keratosis (seemingly 2-3 kinds) be related to pancreatitis and emergency cholecystectomy one month prior?

Needs exam. A sudden proliferation of seborrheic keratoses is known as "the sign of leset trelat", after the french physicians who first reported it. It is quite rare, but it does occur, and it can signal an underlying malignancy, so don't assume it was caused by the pancreatitis; have your doctor do a thorough examination.
Yes. There are skin changes that can be related to GI problems. Is there any continuing issues with either pancreas? Skin may improve with underlying disease. The keratosis are removable if they are acorn.