For disabling the screenshots (which I also dislike), just chmod a-w /home/user/.cache/launch and delete all files in that folder. From that point on, no new screenshots will be saved there.
Yes. Removing testserver is completely safe. It will only be used when Maemo starts in TEST mode, which getbootstate decides if the BSI value returned by the battery is within a specific range, which never happens (or should happen) with a normal battery.