1) Thanks! Supporting personal customization is important and I'm glad that user feedback played a huge role in this. I still would like to see 'Go' and 'Search' buttons, however, for all users. 'Go' is important to a lot of people, non-registered viewers included.
3) Looking forward to this. I can tell you I almost never use the search suggestions because of how slow they are!
In the future, any plans for a feature similar to Google Instant, where you can get dynamic search results as you type when there's a strong match? I'd love to have that option when searching from Special:Search.