Is this supposed to be the true delay of Barrage and Dragon Strike

Skill data doesn't contain speed values.

But character frame data does. Unfortunately it doesn't seem to be consistent (most of them follow the cast_time = sum_of_frame_delays * (speed_number + 10) / 16 rule, but not all) so it's an unreliable way until/unless we know the inner workings of how the game uses those frame delays...