Once you press the Fn button and dial in the bracketing you don't have to hold the Fn button. When the bracketing is on it remains on until you press the Fn button and dialing the bracketing off. You just need to remember to turn the bracketing off.
I assume you can combine bracketing with mirror up, but I've not tried it. Usually when bracketing on a tripod I use a 10 pin remote and just fire off the series of shots.