Back to back events suck, but aren't uncommon. Jeremy Ten did NHK and SC back to back. I/M did SC and CoC back to back. Asada did TEB and CoR back-to-back in 2009.
The Hubbells have split up. I believe he retired whereas she's skating with someone else.
Ok, I see your rationale for C/Z back-to-back assignment, though I hope that they don't end up doing so.
Regarding the Hubbells, I've always considered Keiffer to be the weaker skater than Madison. Do you happen to know who Madison is skating now? Also, is she still with Krylova/Carmelango? I really wish the Hubbells best luck.