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Anything involving blending modes is obscenely complex because it has to be done within the texture space of a single material on a single object.
If you just want transparency you can easily have each semitransparent image as its own object and animate move/rotate/scale each individually in 3d.
But if you want layer blending mode interaction between “layers” you have to move all your objects into a single material on a single object in order for their pixels to be able to mix together 
There’s no way to easily start each fire sprite at a different frame.
Keyframing values on shader nodes is annoying because it’s hard to tell which node you’re looking at the keyframe for. I have 2 nodes where the Factor attribute is keyed and in the graph editor they are both named “factor” with no indication of which node each factor comes from.
