Melapi is basically the Luan you find at a big box store. It is a type of mahogany and will likely stain up redder than you are used to, but maybe that's not a problem for someone who does so much color testing.
Have you used 1/2" ply for the floor before? We used 3/4 but maybe was overkill? My only concern with loss leader "sanded birch" was my experience trying out the Home Depot endcap birch. 0 stars, would not recommend.