Most people don’t realize it their first play through but the date scene in Gold Saucer is not always Aeris. In fact, it’s not always Aeris or Tifa. Aeris, Tifa, Yuffie and Barret all have a chance to partake in the date scene, although getting Yuffie or Barret to join you can be particularly difficult.
Certain decisions made throughout the game determine which of the characters Cloud will go out on a date with. The full walkthrough has little side-notes added as you go, but if you’re interested in all of the possible decisions they can all be found here.
Below is a document written by Terence Ferguson in its entirety that describes how the date scene and its accompanying mechanics work. Links and formatting have been added in afterwards and the original document can be found here: