To Sirlancelot:
Well, the file
spells.zip overwrites same in ...Trent\trent.kfs
To make the changes for Phoenix, it is actually like 3 creatures, but not sure if it will work with existing games: Unzip
phoenix.zip unto Trent\trent.kfs\Creatures
Not sure it will work in existing games, because the 3 Phoenix files in phoenix.zip is NOT in previous games in Trent\trent.kfs\Creatures
But all the other spell changes will work in current game. So if you wanna be sure, just use spells.txt