Same answer as in the Yokohama Grand thread. They are very by the book and your Platinum status does not grant much in the form of guaranteed benefits at an IC. You may get a better room (could be higher floor or different view) and maybe slightly later check out on request, but aside from that expect nothing.

You want breakfast then I suggest to book a breakfast inclusive rate (only Diamonds can chose breakfast as a welcome amenity). You want Club, book a Club rate (only Royal Ambassador get Club upgrade guaranteed).

Japanese hotels (especially the ICs) are by the book and follow the rules closely. YMMV.