I love the command batch so much, nothing anyone can do can sway me to believe that Fox, Wolffe, Kote, Ponds, and Bly weren't a batch and they adopted Rex along the way. Dave Filoni himself couldn't pry it away from me.
But I do love angst. I love Kamino angst specifically, and oh did my brain start doing things when I realized that Ponds is canonically NOT a CC. Canonically his number is CT-411, and only in legends is he CC-6454. Kamino is a horrible, horrible place, where so much can go wrong, so much can happen. Maybe CC-6454 died and CT-411 has to replace him. Maybe CT-411 got quietly promoted to a CC after the rest of his batch was . . . decommissioned but he showed too much promise to go away that easily. Maybe he got mixed up one day and refused to let go of the better life he was handed, and it might have gotten the original CC-6454 killed when everyone else thought he was lying about an imposter.
So many possibilities . . .