namely there is a button with up and down arrows that cycles the merc background from green to yellow to red. what does that do exactly?

any other info about that screen would be helpful. there are a lot of formation buttons and 'auto' buttons that are unexplained.

thanks!

That's to choose their stance:

-Green: stand down and follow me (defensive).
-Red: go hunting (agressive).
-Yellow: I'm not sure, but i guess something in between red and green.

I usually keep them in green and with the speed thingy button on (so i don't leave them behind), switch to red when hunting raiders and back to green when the fight is over.

Okay, that helps. Thanks for the answer.