You got the first part of the strategy, but missed the second - which is to make anakin take his bonus turns asap to burn off Unending Loyalty by removing all protection from, and killing, other ships. Then call in cassian once it's gone, removing taunts and stealth, and taking him out. Your battles demonstrate this but it wasn't stated. One of the big reasons neg mirror matches are tough is because Neg dazes anakin, keeping underending loyalty for a lot longer.
It's a very relevant video even for players that don't use rebels in arena, as often you'll run up against negotiator on defense in TW and GAC.
