This needs playtesting, and i have no time for that atm. :/
One question: Why can't eldar races mix? Corsair/Craftworld/Dark Eldar are no enemies to one or another (every of these factions is able to use the ships of the other factions in the vanilla game, using rules for reserves (corsair+craftworld+prince) or allies(dark eldar + craftworld/corsair). And since we are talking about pirates, there is even more reason to mix them.