They're floating rotors anyway, with the rotors secured to the hubs by the lug nuts. All the 2 piece rotors in the fancy aftermarket kits like Baer, Wilwood etc are all cast iron rotors bolted directly to aluminum hubs, and those are fixed rotors.
Exactly. From an engineering perspective an aluminum control arm is a more difficult part to design, especially the cast kind. Much larger lever arms, multiple fixed and pivoting points, etc. All kinds of modern vehicles use them though. Probably more use aluminum UCA's and hubs than not.
I know Cass was closed for the holidays. Not sure how much the "staff" thing effects him, I honestly don't think anyone other than Cass has answered the phone when I've called.