All those changes would very likely have been made at the factory and other changes would probably also have been made to accommodate them. Sometimes the designers make a mistake and/or a circuit behaves differently to their calculations so these kinds of changes are made, to achieve a performance, function, or stability goal. The changes above are definitely NOT applicable to other situations in this equipment, or in any other equipment. In my opinion using a bipolar electrolytic instead of a polar electrolytic is a bad idea, but a solution nevertheless. (if the reason is that you just don't have a polar one available). Film capacitor replacements for polar or bipolar electrolytics is always a good idea, space permitting.