I’m by no means an expert but I doubt that the whole of the source code of the Nu client would need to be opened even under an NDA.
I’ve had a good look at the differences between the various clones of the Schildbach wallet. The actual wallet code is mainly concerned with the display to the user so the changes between versions are just updates of text (Bitcoin > Litecoin etc.)
The bit of code that does the actual grunt work and interacts with the Bitcoin (or Altcoin) network is a library called bitcoinj (https://github.com/bitcoinj/bitcoinj). there’s quite a bit in there that is specific to bitcoin but clones do exist. (https://github.com/hank/litecoinj). It should be possible to have a look at the differences between those two libraries and transfer the changes to NuBits. Mostly those changes will be things like the version numbers (which give the NuBit and NuShare addresses the ‘B’ and ‘S’ at the start) but there will be some larger changes needed to switch between POW and POS.
I think my point is that although there is quite a lot of work to do to convert the android wallet to Nu, I don’t see how any of it would need a full view of all the source code of the Nu client.
Jordan said this in the Non-Disclosure agreement post
"Those who have access to the source code are encouraged to describe it using natural language (such as English) in any level of detail publicly as people ask questions. Small code snippets (less than 20 lines) may even be posted publicly to illustrate how specific aspects of the software work."
To my mind, that should be ample (than again, I may be wide of the mark. As I said, I’m not an expert)