Incinerate and Incinerate (missile)

I am confused about these.
The Firelord himself has "Incinerate (missile)", but the actual skill data is in "Incinerate" skill.
Can someone explain how exactly it works?

One is the projectile model and one is the ability?

Then the original Firelord would have both of these.
He only has missile :/

I think they made incinerate autocast in one of the patches (it was passive before), but they were in a hurry and didn't make a proper spell, but instead a half-spell that uses the stats of the original passive incinerate. At least, I think it was something like that.

Correct. A marvelous botch job in fact.

So to create my own custom autocast incinerate, i have to base it on incinerate(missile), but alter the stats in actual base Incinerate ability?

What if i want to have more than 1 incinerate based spell on my map?

Then you're in trouble.