Compiler compatibility:
1. FPC which version (2.6.2, 2.7.x, latest trunk)?
2. Delphi which version (7, 2007, XE, XE6)?

GAPI:
3. OpenGL 3/4?
4. Require OpenGL ES 2 or 3 hardware?

Audio?

My thoughts:
1. FPC 2.7.x
2. Delphi XE
We can use unicode and generics.
3. OpenGL 4.x - there is compatibility with older hardware I think?
4. GL ES 2 - most hardware is not capable of GL ES 3 yet.