Right now I can only select my own units, can we get the ability to select enemy units as well(like a spectator can select anyone's units)?

http://springrts.com/wiki/Lua_UnsyncedC ... _Selection
works on enemy units (just tested)

*I want to be able to do draw box etc over an area and all other select commands..

You could redo the whole selection system in a widget, i.e. drawing the box yourself. 'Smart Select' does this already (I don't know how well) and has some filtering logic that you would want (i.e. If a box selects both enemies and allies, they probably just wanted the allied units)

viewtopic.php?f=21&t=26589

this thread is somewhat related, google's post.