Thank god you have setzer with you because he can obtain the fixed dice and the offering which is what makes this challenge a snap. The whole point is to do it without getting locke and relm because then it is too easy. Besides it is fun to beat the game and have a majority of the cast not show up.

Spoiler Alert:
If you do this Terra in the endwill show up regardless if you take her or not . So yeah I have done it. It is funny to see other people rescue Celes instead of Locke.