I may be wrong here, but I actually thought you could set the advise of Marcus and Victoria seperately. At least, I'm sure it's adjustable ingame. Just go to the options menu (you know, by hitting escape) and go to 'game options'. Then you can adjust the advise level between high, medium, low or none. I think this is seperate for campaign and battle maps.

About the commentator you're right though, it's ennoying sometimes. (although I must say I heard worse commentaries during football matches...)