I suspect you have to turn off both Marcus and Victoria when setting the advice level at the start of a campaign. In my preferences.txt file I have
"ADVISOR_VERBOSITY:0" so I assume you can adjust that during the game.

The battle speeches, I just press start immediately to override them. I don't think they affect morale.

In BI, I actually miss the more verbose RTW Roman speeches - in BI you get a couple of sentences only - and I like to hear them before an epic battle.

I don't know if it is changed for BI, but I was rather shocked at how good some of Marcus's advice was during my first BI campaign. He told me to put my archers on the left of the bridge, so they hit the unshielded sides of the enemy crossing it. Nice one, Marcus!