Not quite sure what you mean, so I'll guess. If you mean being able to call out some of the more advanced units (e.g. fire plane) in the early missions, it's possible. You just need to edit the .xml file of the unit.
I don't think there is a leader but I see what you mean. There are usually about 3 people with the big signs - And taking out the 'leader' doesn't effect the other protesters.
It's because you have played a game before loaded the LA mod. You need to restart EM4 and only play on the LA mod. If you play a game then load the mod you will have no commands on your units.
Happy New Year everybody! (Nearly) I'm spending my new year in London and I'll be out in fancy dress tonight! What fun! I haven't go any resolutions this year!