Those are generally on-topic questions, e.g. questions of the first category they usually fall under the comparative-politics tag.
Be more careful with the #2 & #3. There are some questions like those too e.g. Which are the advantages of monarchy? but it sometimes can become a mostly [SE user] opinion-based question, e.g. if the policy proposal is obscure or elaborate enough that few have considered and written about it "in the real world". (There's a close reason for questions that are likely to be answered primarily with [SE users'] opinions, without reference to facts, facts which in this case would be what some others' have already written about the advantages [or disadvantages] of something at least somewhat similar.)
But since you said "question" rather than questions in your title, also beware of asking too many questions in one (question post), as there is a close reason for that ["too broad" it used to be called, I think it was recently renamed to "needs more focus".] So yeah, you can easily (and probably should) ask 3 separate questions. But some may be obsolete in view of answers to others, e.g. answers to questions about who else did or didn't do something may already carry a fair bit of [implicit] explanation as to when an policy is considered suitable (and by whom).
