Interestinger and interestinger... I'm fully expecting them to split metro operations off from the coastal stuff. Either they'll do it straight off the bat or have an interim phase while they gear up for it. Driver and guard wise, it's effectively two different franchises anyway with coastal and metro staff not having a huge amount to do with one another.
They can ping Grove Park and Charing Cross's mainline work down to Tonbridge and Ashford, Gillingham and Faversham can pick up Vic's mainline work and those depots can palm their metro jobs off on Grove Park, Charing Cross and Vic. Half of Orpington can move across to Thameslink with the work and, hey presto, it's all good to go.