Thanks for the guesses, aqualung.
Yes, the sixth through ninth are the sword special attack. Those were some of the most fun to do because they look so silly when you can see them clearly.
Climbing vines looks to me like the standard two walking frames for walking north.
I just tried casting all of the spells. There are a few frames that blink by very quickly, but for the frames that display for more than 1/60 of a second the game uses standard attack frames.
It could be that these were used in Seiken Densetsu but removed for Final Fantasy Adventure? Or not actually used in either?
I may just finish this up, release, and wait to see if anyone reports seeing them. They should be really easy to spot (for me, and anyone who plays my hack) because I drew Xs through them to make them really obvious. Still, I feel like it will be incomplete unless I find these.