You can apply your cats to any of the Clan allegiances. Twilightstar will be returning to her position as WindClan leader shortly and Moonraven is managing those allegiances.
Snakepaw and Lionstorm (a previous RiverClan leader who resigned) are currently in charge of RiverClan. I am managing RiverClan's allegiances but have been holding off on updates until the roster deadline has ended.