[tiermann]

-Today Plugins = Device.
-Anything that's going to run in background or needs to read resources when the device wakes up = Device.
-Anything with hardcoded paths in the program itself which looks in Program Files = Device. Because of this one, it makes things pretty much trial and error.

Everything else should be ok on storage card.

TCPMP should be ok installed to storage card I think. Might just be an issue of editing the shortcut or creating a new one.
HTC Home, Device.
HTC Home Customizer, Storage.
For your camera problem, it may have replaced the shortcuts and then removed them when you uninstalled. Create new shortcuts to \Windows\Camera.exe in \Windows\Start Menu\Programs and \Windows\AppButtons. I doubt it overwrote the original camera.exe.