In my opinion, those are all valid responses. Depends on what you mean by "dodgy". Below are some opinions about some of the related issues. I've tried to highlight the fact that these are opinions by being somewhat lighthearted.
Meta is where the culture is formed.
IMHO you've done right to ask in meta - this is where we form the culture, the norms and the protocols. I also think you've effectively answered your own question, which is entirely valid.
You are the moderator; you are responsible for curation of the site.
Each of us shares the responsibility for the incentive structure that will lead to a better SE. Downvotes, comments, flags et. al. are all valid techniques to incentivize better questions and better answers. We trust you to use all the tools you list in order to improve the quality of the site.
downvotes are atomic
I'm in the minority on this, but a downvote is a downvote. A downvote is an atopic feedback statement "I don't like this question/answer". I don't believe that a downvote obligates me to provide a comment. Sometimes I downvote without explanation if
- I think someone else has explained it well enough. Sometimes I downvote without explanation because I think the explanation is obvious.
- I conclude that the OP would not be helped by the explanation.
- I wish to reinforce the negative feedback loop but don't feel a comment is required.
- The question is part of a trend that will, in my opinion, diminish the value of the SE site.
- I receive telepathic instructions from my pet bird. Downvotes are a privilege that you exercise without oversight or accountability. If you think the question deserves a downvote, then the question deserves your downvote.
That said, I'll admit that if I believe that a downvote + a comment is a more effective feedback loop, then I'll downvote and comment.
Close Votes are not condemnations
Closing a question puts it in a state which facilitates remediation. Contrary to popular rumor, closing a question does not release a plague of locusts to terrorize the OP's home town. Close votes are not a judgement, they are an opportunity. Closed questions get heavily edited to see if we can salvage the question. Closing a quesition also frequently inspires us to start a discussion in Meta to see if we can identfiy which portions of the question are dross, and which are of value. Closing a question can abort a disruptive comment stream and focus attention on what we collectively find might be valuable about the closed question.
moderator attention is expensive
Moderator attention requires manual processing; I try to avoid that unless I perceive something that is really damaging. This is still a subjective judgement. I've recently dropped the threshold for "obsolete" flags (among others) after consultation with one of the moderators elsewhere.