Just to provide a direct answer to your question you can always flag your own answers for diamond moderator attention, just trying it appears to be the only flagging option for your own answers which is probably understandable:
Being an experienced Stack Overflow user you seem to have identified the additional question in an answer that led to the confusion. You could have used that option and paraphrasing your edit summary maybe something like "Please re-consider the deletion, I've removed question-in-answer and changed post to emphasize extra info I provided in my answer".
In my experience the moderators here are helpful and always attend to such flags, but if you're not satisfied with their response or the flag is declined you can always bring it up on a meta post as you've done. But normally as an initial step a flag is the quickest and easiest way there because at the end of the day a moderator will need to undelete it.
For viewing deleted answers the rules are the same as other Stack Exchange sites where users with 10k+ reputation can view them. So if you have a question regarding something deleted in the future where you'd like wider coverage it's probably worth quoting it so everyone can see it.