Very good post! I feel like I understand the concept of slippery slopes much better now. The breakdown into different categories of "slippery slope argument", and cases where they would be valid, is one I find especially useful.

It does make me wonder whether the existence of "slippery slopes" is based on the flawed design of human brains, i.e. hyperbolic discounting, and just the general tendency to alter beliefs for self-consistency or because they sound/feel better. (An example of this would be a real-life version of Gandhi's pill, where starting out with a small not-very-bad act which someone can justify within their moral system, like stealing candy, could lead someone to be more comfortable with stealing in general and end up stealing much bigger things.) Would a non-human 'perfectly rational' alien, one that didn't hyperbolically discount and had no tendency to automatically update their beliefs/moral system so that their past actions weren't evil, still need to worry about slippery slope arguments?