His Pikachu would be heartbroken. Pikachu has been with Ash from the very beginning, and it would likely go into a state of deep depression. It might not eat or interact with others for a long time. Other Pokémon like Charizard would also be extremely sad. Charizard, which has a strong bond with Ash, might fly off on its own, looking for a place to grieve in solitude.
Most of Ash's Pokémon would feel a great sense of loyalty even after his death. They might become more protective of the places Ash loved, like the Pokémon Center in Pallet Town. They would also be very wary of new people or Pokémon that come near, as they are still in a state of mourning. Some Pokémon might even try to train themselves harder, believing that if they were stronger, they could have prevented Ash's death.
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.
Pikachu would probably be very excited. It might jump around Ash, making little electric sparks of joy. Bulbasaur could bring Serena some fresh berries it finds in the forest as a sign of care. Eevee, if they have one, might curl up next to Serena's belly, as if protecting the unborn baby. Their Pokémon would sense the importance of this new development and do their best to be helpful and protective.
Some of his Pokémon might be very confused and sad. Pokémon like Pikachu, who has been with Ash for a long time, would probably miss the adventures and battles they had together. Pikachu might try to cheer Ash up and convince him to change his mind.
Pikachu would probably be very curious. It might zap the lightsaber a bit to see what would happen, and then be in awe of the bright blade. It could also get a bit protective of Ash when he wields the lightsaber, as if it senses the added danger.
Pikachu would be super excited. It has been with Ash for so long and would see Misty as part of the family. It might play more with Misty's water - type Pokémon. Misty's Starmie could be very protective of the new family unit and use its psychic powers to help around the house sometimes.
Some of his Pokémon like Pikachu might be very protective. Pikachu would stay close to Ash at all times, being extra vigilant in case any danger comes while Ash is in this new form. It would also be curious and might try to play with Ash's new fairy features, like his wings if he has any.
Their Pokémon would probably be very protective. Pikachu, being Ash's closest companion, would always be on guard around the baby. It might even try to play with the baby in its own cute way, like using its electric shocks to create little light shows to amuse the baby. Serena's Pokémon, like Fennekin which evolved into Delphox, could use its psychic powers to sense if the baby is in any danger or discomfort. All of their Pokémon would likely adapt their usual habitats and behaviors to be more baby - friendly, for example, making sure not to use any dangerous moves near the baby.
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.
His other Pokémon like Bulbasaur and Charmander would also be startled. They might gather around Ash - Zoroark and sniff him out to make sure it's still him. They could be a bit hesitant to follow his commands at first because they're not used to his new form. However, as they see that Ash's spirit is still there, they would gradually start to trust and follow him again, and they would work together to figure out how to turn him back.
His other Pokémon like Rowlet might be in awe. Rowlet is a curious Pokémon, and having a mythical Pokémon like Tapu Koko around would be fascinating. It could learn a lot from Tapu Koko, especially in terms of using its unique powers more effectively. The whole team would likely feel a sense of pride that Ash was able to catch such a rare and powerful Pokémon.