Wow, that's a lot of features, and I'm not aware of any 3D RTS/RPG engines written with Pascal and also open sourced. The Siege of Avalon engine is pure 2D isometric, and the parts I have ported to JEDI-SDL, compiles with FreePascal and runs on Win32 and Linux, so presumably it should also compile and run on MacOS X as well.

That's the only thing that could potentially come ( not very ) close to what you want. Other than that I suggest reading books like
Programming Role Playing Games with DirectX by Jim Adams ( get the second edition ) and if you search Amazon you should find some books on RTS game development as well. Then get out there and write a kick-arse game!