True ending of Part 1 in PSP2:i

Is the prerequisite for getting the true ending in Emilia's story different from PSP2? I have all story missions S ranked, Shizirou joins me in the final fight, I followed PSP2pedia 's guide on which answers to pick, and I S ranked the Tactical > Side story stuff to get Vivianne and magashi. Even still it gives me the good ending, not the true ending. It won't even give me Shizirou's partner card. Am I missing something?

No one knows anything that could be wrong? I beat it and got the true ending with another character before, following the exact guide. Is it possible only one character can achieve the true ending?

That I can answer. No, you are able to unlock the true ending for every character you have. There could be a different parameter for those that converted their saves.