Well, Cid Kagenou does reveal himself at a crucial point in the manga. This reveal has significant implications for the plot and character development.
I don't have a definite answer for you. The manga might be keeping us in suspense about who Cid Kagenou will end up with. It could be a surprise twist or a character that has been hinted at throughout the series.
The gods might be outraged. They could see Percy as one of their own, especially since he has done so much for them. They might immediately seek to punish the abuser. For example, Zeus could send a bolt of lightning towards the person who abused Percy.
Well, some past gods might be amused. They'd see these modern interpretations of their stories and characters in the Percy Jackson fanfiction as a strange yet interesting new form of worship or at least attention. For example, Zeus might be a bit irked at some of the liberties taken with his character, but also secretly flattered that people are still so interested in him.
Initially, Naruto would be heartbroken. His friends and his village mean everything to him, and the thought that the gods, who are supposed to be just, have turned against him would be a huge blow. However, he wouldn't give up. He would use his determination and his unwavering belief in himself. He might start looking for allies among those who are also disillusioned with the gods or who believe in his innocence.
Well, in many such fanfics, the gods might react with anger. They could seek revenge on the abuser. For example, Zeus might send a bolt of lightning to strike the place where the abuse took place as a sign of his wrath.
Well, El Cid has a basis in history. Rodrigo D铆az de Vivar was a real person, but the stories about him have likely incorporated fictional elements over time to make them more captivating.