Here's a link to the media teleconference that they held today:
http://web.icenetwork.com/video/v1206277383/?query=shibutani
For their SD hip hop rhythm, they talk about how they wanted to do hip hop and do a program that could be appreciated in and outside of the sport, and how got involved with Hokutu Konishi and Aye Hasegawa. They chose Jay-Z because they felt it worked with the music and how Jay-Z stated how Sinatra's music influenced his own and has mentioned Sinatra numerous times in his own music. They also listed a string of other dancers they worked with for the SD. Their Jay-Z piece isn't one you can "download on iTunes" and it's not a specific track as "That's Life" will remain a constant throughout the dance. Instead they customized and sampled a few Jay-Z pieces to go with it in the style of hip hop sampling. They hired a professional to do the music editing and Alex called the blues to hip hop transition "immersive". The idea was "if Frank Sinatra was still here today, what would a song collaboration between Sinatra and Jay-Z sound like?"
For their FD, they found their "beautiful" piece of music a few seasons ago and they think the piece reflects how they're "growing and changing". Alex calls it "captivating" and "emotional". He said the second half of their program is a piece that was performed for them by members of the San Francisco Symphony Orchestra and have been working on the arrangement since spring. They said the choreography was done by "a lot of people" including Peter Tchernyshev. Their decision was stemming from not wanting to be simply satisfied with resting on their results from last season.
They worked with Stephane Lambiel and Jeff Buttle on two different show programs in order to get another point-of-view of their skating.
As to why they didn't do the Challenger Series and instead are debuting their programs in the GP series, Alex and Maia felt this year with the timing of how their programs were developing (constantly getting feedback), they weren't ready until SA to debut them with confidence. I hope this was enough time...
They also said really great things about having Patrick Chan and Nathan Chen at the rink and how it's helped their own training and how they were inspired just by observing their skating.