If you want to change the default sound, open the Clock app, tap Set alarm, then press the menu key and tap the Settings link in the menu. At the bottom of the list, tap the Set default ringtone link to change the default alarm sound.
Even if the power button were disabled in software, you could still long press the button to force a power off. As far as I know, this is a hardware failsafe feature.
I think the panorama feature captures the image as a video, which would result in lower quality and resolution. You can try using other apps. DMD Panorama (com.dermandar.panorama) is nice and works well.
Chainfire makes an app called NoMoarPowah! which lets you schedule your phone to power itself back on at a specified time. It can also suggest a wakeup time based on your alarms. I think your phone needs to be plugged in for it to work, but that s...