I wonder how tough it'd be to implement a 999-like feature where you can skip through dialogue you've seen before? Or implement a dedicated "skip dialogue" button? 'Cause I gotta admit, that's one thing that annoyed me about Corpse Party.
Conceptually, you’ll probably only need two components (depends on how the engine is and your system limitations):
1) your fast-forwarding / skip method (or both)
2) a data structure (refer to your Funnyuncle) for what’s been seen before
If #2 is properly designed and the engine is friendly about it, you can even potentially implement a complete or partial ability to review something you accidentally skipped over (a la the rollback feature in Ren'Py or the “script” feature of L.A. Noire), but that’s icing on the cake.
Because the SNES doesn’t have all that much memory, this may still prove to be more trouble than it’s worth, but then again, you could save a lot of memory for such a feature if you did it (for example) section by section instead of line by line.