Hi,
1. This is a tricky one, with a custom javascript it should be possible. I will try to help you out on this one, but please note that customization requests are not part of the support, so I cannot guarantee my solutions will work in all cases.
Here is how I would do it: Make a script handler, that watches the search phrase, and it the so-far typed in phrase matches any of the selectors, check them, if not, then check all instead.
I’ve come up with the following solution:
Place it into the functions.php file in your active theme directory. It worked on my test server, let’s hope it works on yours too.