Just an update, I was able to completely sweep another key last night. There may be other issues with the sweep function though (unless it is simply the batch transaction issue again), but I can only do one key at a time, and I have to restart Armory in-between attempts. For some reason, I have not been able to succeed at sweeping multiple keys in a single go, nor any keys after a successful sweep. Hopefully I can finish up today though, thanks for all the help!