One more type could be added to James Jacob's Ultimate Magic list; "Untyped Story". Achieving 2 story feats is not the most likely event, but possible. The rule is; "Most story feat bonuses are untyped, and stack with almost any other bonus. However, if you have multiple story feats, their untyped bonuses do not stack with each other. For example, if two story feats gave you a bonus on saving throws, you would add only the higher bonus."
This can be thought of as an interpretation of the untyped rule; "Bonuses without a type always stack, unless they are from the same source", providing you call all the story feats a single source. Not a natural assumption, for me anyway. Most examples of the untyped rule I've seen use the exact same spell cast twice before stacking is disallowed, this is much broader.
I think of untyped story feat bonuses as kind of an undocumented type.