Joe, good point about the flapping velocity changing the angle of attack. It depends on definitions, but I don't think it changes blade pitch. Regardless of what definitions you use, the effect you mentioned is correct.
Beyond my background, but it seems to me that the amount of phase lag change due to flapping velocity, would be dependant on same. For example, small cyclic changes create small flapping amplitudes which means small flapping velocities, which I think will create a small change in phase angle. Large cyclic changes create....fill in the rest. N'est-ce pas?
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You're right about energy, but I'm not certain why you brought it up. It does get confusing when you consider a force applied over a distance, even more confusing when you do it in a certain amount of time. What's easier to see is the starting state and the end state of total energy. If it increases then you've added energy. You don't have to measure forces, distances or times.
If a blade flies off, it has velocity relative to the helicopter, so it has kinetic energy (relative to helicopter).