the dead people in the "real" farplane are real dead people not illusions the one in gadosalam are. also tidus was based on shuyin but the compleate oppersit. (why yuna thinks shuyin is tidus) if havent compleated ffx-2 dont read. lenne and shuyin is tidus and yuna the dream of the fayth created a good verson of shuyin which is tidus who getts attracted to a summoner that is destened to die and trys to stop that from happerning and he sucseeds. same with shuyin but he trys to use vegnagun to save lenne but they both get shot shuyin gose to the farplane and lenne gets absobed into a spheare the fayth knew this which is why they knew that tidus would find a way to defeat sin and make sure the summoner survived if you look they make lenne and shuyin look almost exatly like tidus and yuna. and at the end when you fight shuyin his attacks are very alike to tidus overdrives.

ps if you have read this this is only my theroy and sorry for bad spelling and grammer.