A couple of suggestions / ideas

1) Kevin and Sebastian have done a great job on IDEs, but I'd recommending dropping the IDE. This allows a focus on the tool chain and library and avoids wasted effort. Instead, package something like Eclipse or Anjuta (why reinvent the wheel).
2) drop support for old AMS versions; it is easy to upgrade with a link cable or PC. This reduces complexity of the project. It might be pretty safe to pick the very latest versions of the OS. I don't think TI puts much effort into these calculator models anymore, so future OS versions are somewhat unlikely.