If Michelin gets the contract, I'd assume their current P2 tires (or an updated version of them) would be the tire of choice for the P class. They would probably employ the current GTE tire strategy in the future as well for GTD.
Also, this end of the Conti contract means the end of the sponsorship for the 2nd tier championship. I wonder if the new tire contractor will be required to sponsor said championship or if an outside sponsor will be found.