Rhubarb is a vegetable, so yes it is fine. Cocoa powder probably technically belongs to the nut rung but if you check the label and remember its pure cocoa not hot chocolate - green and blacks, bourneville and tesco do good ones- then it should be less than 1g carbs per tbsp. no recipe I use requires more than a tbsp so it's a matter of sensible moderation. For sausages you must choose ones that are all pork with no breadcrumb filler - there are some examples in the shopping list sticky.