If you're referring to the normal in game stages, given that there isn't an in game timer for any of them, I don't really think they're particularly well suited for having ILs. If one of the other mods wants to add and handle them, that's fine but I don't think this is a case where they're needed. If you want to practice them as ILs or if another mod disagrees with me and wants to maintain them, by all means go ahead.

Yeah, I kinda feel similar to Ghoul in that the story stages do not lend themselves to IL runs very well. In addition to what he said, stages are also influenced by prior gameplay, such as drinking in the bar or carrying over items from previous stages, so trying to define rules for ILs would be rather arbitrary.