What do you mean by a USB? If the internal webcam was connected to the laptop's USB bus, then yes, you could. However if this is not the case you will need a controller inbetween, a DSP or CPLD.
If the HDD doesn't turn off by itself or does not have a power switch, you will have to unplug it. That's the way it works. I happen to have a WD 1TB one that automatically turns on/off depending on USB activity, might want to try one of those.
Since when do backups ever reach high read/write cycles? They're backups. If you're doing your job well they aren't even going to be read. The flash controller takes care of wear leveling and invalid blocks. You seem to be highly exaggerating the flaws of flash; Yes it has lower read cycles than...
I have a Wii Remote Plus from a Black Wii recently bought and I've had no difficulty using HBC or USBLoader. Hope this will help with the 'investigation'.