Alright I was able to enable first person in the odfs of flying vehicles so that you can switch first person to third person at my lesure. However, when I tried to enable it in ground vehicles such as the spider walker it did not work. This may be because in BF2 the land vehicles don't have the ability to do that switch ingame as they do in aircraft. Is it possible though to enable it in the odf so that you can have custom first person for a land vehicle without having to have it be forced to only first person by putting
forcemode = 1? Just removing the two \\ before the line didn't do anything for me but perhaps I am missing something?

Nope, thats all there is. Theres no controller setup in the game to switch land vehicle view (they took it out), so if you want it, you must force it.