I do not see why not - there are a number of heuristic sets that have been designed for evaluating a wide range of domains - there are heuristics for games on mobile devices - i think care needs to be taken over selecting an appropriate heuristic set - Nielsen's may be to generic and not offer adequate coverage of the domain -

You could always look at::

Enrico Bertini, Silvia Gabrielli, and Stephen Kimani. 2006. Appropriating and assessing heuristics for mobile computing. In Proceedings of the working conference on Advanced visual interfaces (AVI '06). ACM, New York, NY, USA, 119-126. DOI=10.1145/1133265.1133291 http://doi.acm.org/10.1145/1133265.1133291

I believe yes. They have been adapted to so many other situations, I do not see why not adapting them in the case of smartphones.

In my opinion the Nielsen/Molich heuristic are a good starting point also for smartphones and tablets. But in mobile applications also other criteria are important. For example the “one thumb- one eyeball” principle is very important. Maybe you can find some useful heuristics in http://www.abookapart.com/products/mobile-first . You should also think about the platform specific guidelines, the iPhone approach is sometimes different to the Android way.

From the point of view of design, it's necessary think in the deisgn of small interfaces.

You could find a lot of guidelines, from Android, iPhone, Windows platforms, etc...

Yes, Nielsen has a good book about the usability of mobile devices and could help as reference about how apply usability techniques.