Ginsue,
On your third option, I beg to differ. Within the last year, and within about a week of each other, I inadvertently started 2 duplicate threads for 2 different members.
In both instances, I searched via sorting by title, with no success. I was fairly sure I had previously left feedback for at least one of them, so I was perplexed..

Doesn't always work, and in fact, I have run into the same situation a couple times recently, and had to get creative to locate their threads.