What you've seen are official translations, not fan translations. The only N64 game that has been fan translated so far it Sin & Punishment and that was done by retexturing. If you know exactly how the text data is stored in the ROM and know how to hack the game effectively, then you might have a good start at translating OoT. I don't think retexturing will help you much with OoT because of the way the letters are handled in the game.