At first, his friends would be in disbelief. But then, they would start to adapt. Dawn might see it as an opportunity to study a Pokémon from a different perspective. Gary could be both amused and intrigued, and might offer some scientific theories on how it happened. Overall, they would all be concerned for Ash's well - being and work together to either help him get back to normal or help him thrive in his new form.
His friends would be very shocked at first. Misty might be a bit worried and try to find a way to turn him back quickly. Brock, on the other hand, would be more curious and start observing Ash - as - Pikachu to see how his behavior has changed. His Pokémon friends would also be confused. Pikachu himself might be both excited to have a 'Pikachu - like' friend but also a bit sad that his trainer is in this strange state.
His best friend Pikachu might be a bit confused at first but would quickly adapt as it still senses Ash's essence. Brock would probably be very surprised and might offer some comical comments or advice on how to handle the new situation. Misty could be a mix of shocked and intrigued. She might be a bit jealous of Ash's new female appearance at first, but then would support him as they are friends.
At first, his Pokémon would be startled. They've always known Ash as a human. But then, they would start to adapt. Some Pokémon, like Squirtle, might try to play with Ash in his new form, thinking it's a new kind of game. However, his more loyal Pokémon, like Greninja, would be determined to find a way to turn Ash back. Greninja might use its special bond with Ash to try and communicate with him on a deeper level in this new form, to understand what happened and how to reverse it.
His other Pokémon like Charizard would be completely bewildered. Charizard might initially think that this Eevee is just some random Pokémon near its territory. But when it senses something familiar about the Eevee, it would be hesitant and curious. It could try to communicate in its own way, like using small bursts of fire to get the Eevee's (Ash's) attention. The Pokémon that Ash has a closer bond with would be more determined to figure out what's going on and how to help him.
I think his friends' reactions would vary. Naruto's closest friends like Shikamaru and Kiba would quickly realize that they need to support Naruto. They would see that despite the strange new form, it's still Naruto. Sakura would be more emotional, she might cry at first but then pull herself together to help. And Sasuke, he would probably see it as an opportunity for Naruto to gain more power, but also be cautious in case the Titan form has any negative effects on Naruto's mind.
His friends would be extremely shocked at first. Misty might scream and be really confused about what's happening to Ash. Brock, on the other hand, would probably try to stay calm and start thinking of ways to reverse the transformation right away. They would all be worried about how Ash is feeling in his new form and if he's in any pain. They would also be concerned about how they can still communicate with him effectively, since he's becoming a Pokemon.
His friends' reactions would be mixed. Shikamaru would be like 'This is such a drag.' But he'd also start thinking of strategies to deal with the situation. Ino would be all about helping Naruto with his new look, like suggesting new outfits that would suit a fox girl. Choji would be more focused on making sure Naruto is still the same person inside. He'd offer Naruto his snacks to cheer him up. And Hinata would be blushing a lot, but also be very supportive, saying things like 'Naruto - kun, you look... different, but you're still you.'
Ron would probably be both shocked and a bit awestruck at first. He might make some typical Ron - like jokes to ease the tension, like 'Blimey, Harry, you're a dragon! At least you'll be good for scaring off Snape now!'. But deep down, he'd be worried and determined to help Harry get back to normal.
His friends would be quite shocked. Neville might be a bit scared at first, thinking it's some new dark magic. But then they'd all come together. Ginny would probably be the one to try and comfort 'cat - Harry' by giving him some fish or milk, thinking that's what cats like. And they'd all be determined to get him back to normal as soon as possible.
Sakura might be initially shocked and a bit jealous at how cute Naruto - as - a - girl is. Sasuke would probably be confused at first but then act indifferent. Kakashi would be his usual calm self, but might crack a few jokes about Naruto's new look.