They all strike me as being similar to thoughts. I would use italics. One downside to italics is that it is such a busy font, I have to use underlining to show emphasis within italics. Not really a big deal if you self-publish. The other options for showing emphasis within italics didn't work for me. I tried using regular font within italics to show emphasis, but the occasional word in regular font within a sea of italics is not easily distinguished. I also tried bold, but it stood out like a sore thumb, dragging the eye away from what I was trying to read.
You're up late. :-)
Dirk