Bushes didn't need anything to go in. I used a little bit of copper grease to make it even easier, but if they're nice and clean and the inside of the beam where the bushes mount is clean and smooth too then it goes in so easy by hand, no force.
Brakes can remain in place. Just removed the calipers and leave them on the car, supported. The beam will have the discs attached still obviously. No need to disconnect any brake lines.
You'll need an assistant to help line up the beam and also to remove it, it's pretty heavy.