I think Keith's closest friends within the blades are most affected. If he's younger, they might become more overprotective. If he's older, they could start relying on him more for advice. For instance, if there's a character named Lance who was previously on equal footing with Keith, now he might see Keith in a different light depending on his age.
Well, it could change the relationships in the story. Maybe the other characters start treating Keith differently, either more protectively if he's younger or with more respect if he's older. It might also affect the group dynamics within the blades.
One of the main characters could be Shiro. Shiro has always been like a big brother to Keith. So when Keith turns into a girl, Shiro would be there to help him adjust. He'd make sure Keith is safe and comfortable in his new form. Also, Hunk could be a main character. Hunk would probably be the one to offer emotional support and cook some comfort food for Keith during this tough time of adjustment.
Keith will likely be defiant. He has a strong sense of justice and will not be easily broken by Zarkon. He might try to fight back immediately if he has the chance.
There is. Try searching on different fanfiction websites. A lot of fans are creative and come up with interesting scenarios for Acxa and Keith as siblings. You may have to dig a bit through the search results, but it's likely you'll stumble upon some great reads that really capture the essence of their relationship.
It could be an old enemy of Keith's, someone from his past who has a vendetta against him. Maybe a former rival from his days in the military academy who has now turned to more devious means.
I don't know who the creator of 'animation keith's story' is. There's not enough information provided to determine that.
He might be polite but a bit guarded at first.
Lance's family might be really welcoming. They could see that Keith is an important part of Lance's life and embrace him right away.
There might be. I'd suggest checking out fanfiction communities dedicated to Pokemon. Sometimes, smaller, niche communities can have really well - written fanfics that might not be as easy to find on the bigger platforms. You could also ask in Pokemon - related forums if anyone has any recommendations for 'pokemon ranger keith x kate' fanfiction.
One great 'Hurt Keith' fanfiction is 'The Trials of Keith' on Archive of Our Own. It delves deep into his emotional turmoil after a tough battle. The author really captures his pain and how he struggles to come to terms with it.