And regarding a backup for commercial crew... In all likelihood, Orion on EELV is that backup, even if SDHLV is built.
In my opinion, the Orion CSM (CM plus SM) should comprise only 2/3 of the Orion Spacecraft, the other 1/3 being the MM. The Orion CSM must not be made too heavy for the EELV launchers to be able to send it to an ISS type LEO. When being flown as a LEO taxi to a LEO destination, there should be no MM included and this would constitute the LEO version of Orion, flyable on the Atlas or the Delta. For LEO applications Orion is simply a taxi. For LEO missions where LEO itself is the destination or for BEO missions, the MM will need to be included and would rightly need to be flown on the SLS. The goal is to make Orion relevant to both LEO and BEO. The way to do that is to design the CM to be taxi space, not living space. But this is a subject for another thread.
WRT what happens with a CR and no new Authorization Bill, then I believe the current existing Authorization Bill would govern policy. I believe that is Public Law 110-422. That Bill does indeed encourage development of Commercial cargo and crew, and instructs NASA to use it when it becomes available, but doesn't address funding
this effort, which would be in a different, "Appropriations" bill. In that case a CR with no new Authorization Bill to specifically address developing Commercial Crew would be a severe setback for Commercial crew because the current Appropriations Bill doesn't address it. Once the Authorization and Appropriations bills are enacted into law the Administrator does have certain latitude in his use of the funding, but it must still comply with the intent of the law. The current Authorization and Appropriations bills would not give him that latitude. Here's the link:http://legislative.nasa.gov/PL%20110-422.pdf
Now note please that this is an "Authorization Bill" not an "Appropriations Bill".
51D, if you don't mind, would you comment on this?