Dear Yichau,
Regarding (1), the torque controller for the NREL 5-MW baseline wind turbine does not have the same logic as the simple induction generator model. If you wish to implement the simple induction generator model rather than the actual torque controller, you’ll have to make your own assumptions for your own purposes. The simple induction generator model is explained on page 11 of the old FAST User’s Guide: nwtc.nrel.gov/system/files/FAST.pdf.
Regarding (2), I’m not sure I can really answer your question because I was only loosely involved as a co-author of that report and did not help develop the Simulink models. From the report though, it says that constant block associated with input 1 is the reference generator speed (i.e. the rated generator speed) and the constant block associated with input 2 is the reference power (i.e. the rated power).
Best regards,