I thought that Aeris died while summoning the white Holy... Evryone was like *omg I hope she managed to do it on time before she got stabbed through the heart* and at the end the Holy still comes ...

There are too many inconsistencies in the game for Aeris, the programmers were sloppy if they decided to not bring her back to life. Other wise there is too much evidence that suggests you can bring her back ... That giant fish has something to do with it I know it ><