Okay, so, Charlie came back by, and I managed to get outside into the carport while they were hiding under the car, without my cats going outside to attack them. I sat nearby and talked to them a bit, and they only hissed at me. So, I'm pretty sure they're feral and not interested in being adopted. I guess I'm going to stop leaving food out for them, and I should probably just call Animal Control and see if they want to do their thing.