Just so this receives an answer of some sort, importing sound effects as far as I know is still an uncharted territory. Even Shall here it seems was unable to import the FFV spell sounds to go along with all the imported animations as he resorted to using the pre-existing FFVI ones:
https://www.youtube.com/watch?v=cYo45VCfQ6U
It does look to be about the same as importing instruments, though, which is much more documented and accomplished thus far - looking at the C5 disassembly the sound effects also use ADSR data, wave rate multiplying values, and a table, just like the instrument samples... The main thing I believe is that you would need to first have the hex data of the sound effect you are wanting to import, once that is obtained you could place it in the ROM and re-point a sound effect in the table to that data, then adjust the corresponding ADSR and wave rate values which would most likely be a pain to get right if you don't know what to change them to exactly. But in the end you would have the new sound effect in the spot of another.
https://www.youtube.com/watch?v=cYo45VCfQ6U
It does look to be about the same as importing instruments, though, which is much more documented and accomplished thus far - looking at the C5 disassembly the sound effects also use ADSR data, wave rate multiplying values, and a table, just like the instrument samples... The main thing I believe is that you would need to first have the hex data of the sound effect you are wanting to import, once that is obtained you could place it in the ROM and re-point a sound effect in the table to that data, then adjust the corresponding ADSR and wave rate values which would most likely be a pain to get right if you don't know what to change them to exactly. But in the end you would have the new sound effect in the spot of another.
We are born, live, die and then do the same thing over again.