Thanks CyanPrime.
Been doing a lot on the effects editor:

Click for full resolution. One effect is made up of multiple particle emitters. For configurable properties, an emitter has: duration, life, life offset (fast forwards life at spawn), delay (before it starts, for syncing with other emitters in an effect), emission (per second), size, rotation, velocity, angle, wind, gravity, transparency, tint, spawn width, spawn height, and spawn shape (point, line, square, or ellipse -- edges or area). Did I miss any?

Depending on the property, the values can start at a random range and end at a random range, and you can add any number of points to the little chart to make it vary over the duration of the emitter or particle.
Once I get the effect right in the editor, I just save it and use the file name in my game code:
1
| target.addEffect("heal"); |
Creating abilities and effects is very easy, so I should be able to have quite a lot of them!
I have a little more to do before I'll update the applet. I'm going to make a projectile effect next. Then for my first fancy ability, I'll add a fireball ability that has effects as the caster charges up, a projectile effect that flies to the target, and an explosion effect on impact.
