In the tech/startup world, I would advise against doing this sort of in-depth questioning of references. Really, most of these checks are going to be done by your HR team/recruiter and all they're really trying to establish is that they are who they say they are. They're not trying to establish how awesome the candidate is.
The "awesomeness" part is something you need to establish through the rest of the process:
* interviews with the hiring manager and team
* code samples via Github or some other project
* a coding challenge that is reviewed by several people
There are some other things you can do. I for one am a proponent of the "social interview" idea. I like to have candidates come over for some part of the event where they aren't sitting in a conference room and you aren't asking them technical questions. See if you can have a conversation with her, figure out if he's friendly and interesting, decide if you're willing to spend the next two years "in the trenches" with this person.