self powered drives will get power from the hopper a usb port is all that's needed
Short term. Long term- ???
I suggest only powering them when in use
Doesn't matter if it's external or internal, because you can't duplicate the recordings as a backup.
You can use h/w RAID 1 arrays, like I did. End up with two identical HDDs.
Fat lot of good it did me. I still lost almost everything, across several EHDs, some RAID.