I know how to make a video, that's not the question. The question is, how would I easiest make a series of videos where I watch player A from the perspective of player B, and player A has a different username in each video? I would prefer to do this with player A and B connecting over LAN and without buying lots of different accounts, but I suspect it may not be possible. Do I need a modded server or can it be done without one?
EDIT: I have accepted an answer because it works to do exactly what I wanted, but frustratingly it also has a side-effect which means I can't use it - the visible skin of a player with a changed displayName reverts to default. I'd much appreciate a solution which lets me easily control both skin and display name easily, preferably under LAN connection.