What is the protocol for flagging my own questions if I now believe it could possibly be deserving of being closed? Should I remove the question instead - or flag and get moderator consensus?
Deleting your own content is a nuanced concept.
- By default, you are free to edit and/or remove your posts as you see fit, but there are exceptions.
- You should not vandalize your own content. Often people will rage quit the site, and delete and/or vandalize every post they've made. This is heavily discouraged on every Stack Exchange I know of.
- You should not fundamentally alter a question. "Fundamentally altered" essentially means you change your question to a completely different question. Improvements to a question that don't change it's essence are okay and even encouraged.
- The system will automatically prevent you from posting answers if your account has fallen below a certain quality threshold. Deleting your own posts counts against this quality threshold. Once you have a significant pool of reputation based on quality posts, you shouldn't have to worry much about this.
In general, If you feel like your post ought to be closed and deleted, and you feel strongly enough that you would flag it, then you are probably okay to delete it yourself. If it has upvoted answers, the system won't let you delete it, and if that's the case, then you can flag a moderator.