OK. To clarify:

The Artist/Source/etc. buttons work in normal operation (i.e. when listening to music) by looking for another track from later in the playlist with a matching artist/source/etc. It only inserts one track. Keep pressing it to queue up more.

In v2.0, if you press-and-hold the button, this has the opposite effect -- it's the "hate artist" feature. It'll remove (or at least swap to the end, I don't recall) those items matching the current artist or whatever.

The title button does nothing in this situation -- there's no code in there to support it. We were talking about doing fuzzy matching on the rest of the playlist, but this feature is not likely to make it into v2.0

Right, on to searching:

You can toggle through the various search screens by repeatedly pressing the search button.

We did talk about having a two-press scenario (you've called it direct search), where you'd press the search button, then one of the artist/whatever buttons to jump to that screen.

We haven't implemented it yet.