I wouldn't talk in absolutes because having a ton of negotiating leverage can make everything fair game. But in an run of the mill deal, it's pretty tough to make a VC give up anything that's not in brackets.

Ya. If you are blowing up and VCs are knocking down the door to throw money at you, you can write your own ticket. Look at Zuckerberg who was able to do many rounds of funding while maintaining total board voting control.