Thanks for the reply, sol, and you are correct in that the e-brake is built into the rear rotors.
I've also tried beating it with a deadblow hammer but it seems to be free of any rust that's sticking to it.
As an update, I did find the adjustment gear and loosened the e-brake as far as it would turn. I've got ~4mm of clearance between the inside of the rotor and what I think is the e-brake pad. I'm able to ease the right side of the rotor a bit further now until it gets caught by the left side. I'll take some pics tomorrow so it's a bit more clear.
For some reason, it feels as if the rotor is somehow tangled up with the left side of the e-brake
. When I pull on the rotor to come off, I hear a spring being stretched.