IJCT
Best I can tell from looking at the events is they have to be done in order, and triggers can be run at any time.
Basically the the three events are:
"every tick" which calculates the stating velocities
"the input check" which launches an actual physics object with the calculated velocities
"the loop" which takes the calculated velocities and simulates physics steps to find the path of the ball.
So if you want to launch a ball with a trigger such as a function you need to run the every tick event first somehow. Could be as simple as copying it.