Steal, GP Rain, and Steal GP as Spells?

I think you are on the right track. Spell $EE is Battle used by the Fight command ($00). However, script $00F2 does not directly refer to an animation script, it is instead used in the C1/BECD function I think, which look to be responsible of animation among other things. It worth a shot testing what $00F2 would do on a spell cast. Adding effect $51 should logically make the character steal and steal sprite animation is indeed script $007B.

Capture on the other hand does not have a spell related to the command I think and has a different animation function than Fight. The calls are in C1/B775 table and capture animation function is at C1/BBA5. Offering code only affect Fight and Capture commands but Gembox might work.