Hi wesleydw,
You seem to have already played coopordie with the standard Quake2 engine. For enhancing your experience with a better engine, you only have to install one, and launch it in place of the standard engine.
For example, after installing
EGL Quake2, you have to modify your "coopordie.bat" file and replace quake2.exe by egl.exe.
Most recent Quake2 engine could run coopordie. Unfortunately, as far as I know, Quake2evolved and Quake2XP have broken the compatibility and use modified DLL, so they can't run coopordie (except if someone want to adapt them).