My experience with making a booking for more than one room at the same property, for the same nights, under my name with my Plat status, is that the other party also received an upgrade to Club level at a Sheraton, as did I. [Second party's name -- family -- was included in the "special requests" box when booking on web site.]

I received points for both rooms as they were billed to my portfolio, a single Plat amenity and web booking bonus of 500 Starpoints each, but as expected just received one stay credit, and the three nights [rather than two stay credits and six nights].