some short reply, more later:
a) we have not been hired by anyone
RoR will continue to exist as free and open source game. We are currently integrating a new terrain system and terrain-reload-ability into it. (lots of work! http://redmine.rigsofrods.com/projects/ror/activity)
c) the engine we presented in the tech demo video falls not under GPL because it was written completely from scratch
about our goals, we will see
^ Straight from Tdev at ROR