Power against brakes will always give better perf than rolling. With rolling you are using TODA before you have take off thrust.
Not necessarily so...can be type specific.
B707-320B (advanced cowl) aircraft are a specific example, due to auxiliary inlet door design.
Maximum Achievable Takeoff Weights were (1) Roll-On Takeoff, (2) Standing Start, and (3) Rolling Takeoff in that descending order. The AFM went on to explain that a properly executed Roll-On Takeoff was one where the aircraft had a minimum speed of 10 knots at the normal SOT.
Spot on, and applies to the above referenced type.