Sam's Favorite Chocolate Cake

Its common practice for me to freeze cake layers before decorating, especially if they're going to be tiered/intricately decorated. I then torte, fill, crumb coat, frost, etc. semi-frozen layers. I try never to refrigerate baked goods because, a. they don't need to be refrigerated and b. the environment tends to speed up staling. Since you're just pouring ganache over the cake, and keeping it only a day, you could get away with just wrapping it tightly and keep it on the counter without any noticeable damage to quality. Whatever is more convenient for you...again, since its only a day I don't think it matters if you freeze it or keep it at room temperature.

As for the chocolate debate (which I'm unaware of), there is no difference between "bittersweet", "semisweet" and "dark" according to the FDA....but in my personal opinion, bittersweet contains slightly less added sugar and more liquor.