How to make a fireball that can explode, that is shot via procedure

It is possible to make a projectile that lights blocks on fire, and explode, but only if you are using the "ranged weapon" function on an item, because it shoots the projectile itself.

But say you wanted to make an item that produces a projectile that explodes or sets blocks on fire, via a procedure. 

Problem.

The only projectile spawning procedures are "arrow of type [projectile]" "fireball of type [projectile]", and "throwable projectile of type [projectile]"

The problem with these, is that they re-classify the projectile with overwriting parameters, and secondly, you can only ever use the arrow one, as there are no ways to create a projectile classified as a "fireball" and "throwable" by those parameters.

Or, maybe there "is" a way to make a projectile with those classifications?

.. Either way, the result of this issue, is that you cannot create a (custom) projectile that is shot/spawned via procedures, that can explode, or set blocks on fire. It simply can't be done.

Which means by association, you can't make projectiles that are created by other projectiles, that explode, or set blocks on fire. Which means you can't make things like cluster bombs.

Why does this issue occur? Because when using the "Arrow of type [projectile], it ignores the projectile's triggers, thus ignoring any  procedures that would have triggered, thus firing a mostly-inert, triggerless projectile.

Ironically, it does still use some of the initial values of the projectile, like it's damage.. Which means you have to work with using TWO different damage formulas when using projectiles this way, as even if you set the default projectile's damage to 0, that's still doing 0.5 due to the stanky-jank code.. So you have to keep that in mind, when customizing the "arrow" projectile's damage.

MID-TROUBLESHOOTING UPDATE:
What's really baffling me though as well, is that I just assumed this was because I "thought" it was just removing the projectiles triggers.. But I just made a projectile that enacted a procedure to light the mob it hits on fire, and when shot via procedure, it worked.

.. So, "Some" procedures work on a projectile fired via procedure, but some don't?? What spaghetti code must I unravel to fix this issue?

I'll continue to troubleshoot this, and post a solution if I find one, but please, if anyone's got some knowledge on this, let me know.