1) Three files - glide.dll, sst1init.dll, fxmemmap.vxd. Not sure about the fxmemmap.vxd, several games aren't including this file.
2) You can leave glide.dll and sst1init.dll in the system dir. Because Voodoo3 will not use glide 2.1.1 at all. And several installers are searching for these files.
3) To be more precise:
Cybergladiators - no glide 2.1.1 is included on cd. You must install glide 2.1.1 from another source.
Mechwarriors: 31st Century Combat 3dfx - no glide 2.1.1 is included.
Outlaws (with 1.1 patch) - no glide 2.1.1 is included.
Pandemonium! - glide 2.1.1 (from 21 Jan 1997) is included on cd and is installed in the gamedir. No fxmemmap.vxd is included.
Pod 2.0 - no glide 2.1.1 on the cd. You must install glide 2.1.1 separately because you can't even install the 3dfx version w/o glide 2.1.1 drivers.
Pod Gold is using glide2x.dll and don't need glide.dll and sst1init.dll in the system.
Scorched Planet - glide 2.1.1 (from 25 Jul 1996) is included on cd and is installed in the gamedir if Voodoo1 (Rush?) was detected.
Tigershark - no glide 2.1.1 is included.
Time Warriors - glide.dll and sst1init.dll (from 23 Jan 1997) are included.
Glide2x games with glide.dll/sst1init.dll on the cd: Asghan (glide.dll and sst1init.dll, 23 Jan 1997), Joint Strike Fighter (20 Jan 97).
Joint Strike Fighter have 2 versions of glide 2.1.1 - Win95 and WinNT. And there are 2 more files - genport.sys and mapmem.sys...
Plus there is Glide 2.1.1 SDK. Again there are genport.sys and mapmem.sys as the WinNT driver files...