Okay, I take it you haven't read the manual.
1) Resume after startup automatically resumes playback. Since you have to press a button to resume, that function is working as intended.
2) The Play button is the resume button. If playback is already happening, it brings you to the WPS. If playback is not happening, it resumes the last used playlist. Even across reboots. You can never start a new playlist with it, ONLY resume, which is why it's not reshuffling.
The center button, called Select, is how you actually launch a playlist, which is the only way to trigger it to reshuffle and shuffling only happens when you start a playlist, or when the playlist reaches the end and starts over (if the settings are right for this).
I strongly suggest you read the manual and learn how to operate the software, as you would have received your answer in a much quicker manner as well as not having to install other builds.