In my reading of the Help page, both of these are already on topic. I don't think we are systematically closing questions that fit into those categories, so I don't think there is a practical problem that needs to be solved. However, we could make our Help more clear.
Questions about political movements are generically on topic. Asking about the characteristics or properties of any movement is on topic because the "conflicting egos" category covers this. We could expand and clarify that point though:
- Public Opinion - Questions about "who supports what" are on-topic. This includes questions about aggregate public opinion, political party membership, ideology, movements, as well as the statements of notable political personalities.
Questions about philosophy are on-topic in practice, but I've already pointed out in another question that our Help doesn't support that. I would suggest we make it clear that questions about political theory and philosophy are on-topic to clear this up. We would need to be clear about what makes a good political theory question/answer.
Your point about "customs" to me sounds a lot like "strategy". Questions about social customs (even insofar as they could involve politics) are off-topic. For example, this question about body language was closed because of its emphasis on social custom.
Your examples are different. They all involve the political process. To me, these are captured under "working themselves out". Blocking nominees, resigning from office, etc. are all part of how politics happens. In the wording of the Help page, they are part of the "[process] by which policy is made".