Thanks for getting in touch! The difference between the ActionID and StepID can be seen if you look a the API for the deployment process on a project. Essentially, steps contain actions but actions don’t contain steps. A good example of this would be two steps configured as a rolling deployment. Octopus has a single StepID for both of the nested steps which each contain their own unique ActionID. This allows an additional layer of granularity for the data when building projects.
As for your second question, the StepID for the individual step should not change, same goes for the ActionID in a step. So if you are aware of this ID and later edit the display name, you can find the step using the ID.
Does that help?
If you have any questions at all here, please don’t hesitate to let me know.