I'll repeat something I said earlier - FFG has already established a faction that includes Han, Lando and the shadier side of the Rebellion - it's called Smugglers and Spies (from the LCG). No reason they couldn't add a 4th faction down the road and do everything being discussed in this thread.
Because what ships would it have? The Rebels have stolen all their pilots and ships. It exists in the LCG because Scum and Villainy needed a lightside mirror. LCG also has Sith and Jedi factions, and nobody expects to see them.
Smugglers and Spies is not a faction in the sense of X-wing, it's one of the three classes under the Light Side faction.
In the LCG, Scum and Villainy are the dark side aligned criminal element, and Smugglers and Spies are the light.
In Imperial Assault Campaign, Scum and Villiany are generally a criminal element with loose ties to the Empire. In Imperial Assault Skirmish either side can recruit them as far as I know. The lightsider Scum are part of the Rebels.
In Armada, Scum and Villainy are rolled into the Empire, and "Rogues" rolled into the Rebels.
In X-wing, Scum and Villainy is opposed to both Rebel and Imperial interests fighting both (FFG went to great lengths to establish this). Therefore, a fourth faction is then logically fighting and being fought by all three.
Smugglers and Spies is part of the Rebel faction in all but the LCG, where it splits off for parity only. It's not realistic as a fourth faction, and the "the LCG does it so X-wing will" logic also gives us a Sith and Jedi X-wing faction.
I'm not saying X-Wing will do it. I'm only suggesting that there is a way to get a new Han/Lando YT-1300 without forcing them into Scum & Villainy, where - I think it has been adequately argued - they don't belong.