So to pick an enchantment you must have at least 1 skill point allocated to the skill in question. What I want to know is, does the skill inherit the bonuses (if any) from hard points placed in it?
For example, I take the Fireball enchant which makes enemies explode on death for 50% of Fireball’s damage. If I take the node that increases the AoE by 50% on Fireball, does that apply to the enchantment effect as well?
Yes. It the bonuses do apply.
Yes. However if the bonus says upon casting, that won’t apply.
OK, so that means the +50% AoE bonus will not apply since its says “Casting Fireball”.
Bummer, thought I was onto something.
More than likely it won’t apply
This won’t work no. It’s still very strong though! And that’s probably why.
You can select a skill for enchantment and also grab the upgrades you want.
Go back to your “assign skill” page and if you pull up the tooltip for each enchantment slot, it will show you which upgrades work for that skill.
Gets tedious after a while but you’ll start to remember which skills carry which upgrades through enchantment.
But generally speaking “cast” in the description means no.
I did notice earlier that spell procs from the aspect that casts while unstable currents is on CD benefits from other aspects though.
Finally saw a 2x Lightning Spear proc off casting teleport, I’m sure it’s happened before, but I’ve never noticed. 
Would be nice if everything just worked together without all these small silly “classifications” on specific skills/upgrades though