Yeah scripted lifebar is the way to go, not only for differing colors by player#, but also if you want to keep those nice gradients. You can either draw it as a set of lines stacked together to form a single bar with gradient, create the gradient by using a script spawned overlay or a combination of both.
Fortunately it's not nearly as tough as it sounds. The most difficult part is just getting the math worked out for placement on screen, and you have to worry about that with or without script. Golden Axe Remake has a nice example of how to do it (look at update.c).
DC