Japanese Voice Actors & Actresses Currently Available for Their Voice Roles of Any of Ash's Old Pokémon?

From the original Japanese version of the original to Sun & Moon series of the Pokémon anime, I knew that the original Japanese voice actors and actresses have provided their voice role of all Ash's Pokémon. I have thought that the anime writers and producers have originally been planning on Ash bringing out any of his old Pokémon from at Professor Oak's Laboratory and/or from at Professor Kukui's home or Primeape and Squirtle returning to reunite with them. But sadly, it is unknown whether or not which voice actor you think that will be available to replace Unsho Ishizuka as providing his second Japanese voice role of Ash's Kingler, Muk, Swellow and Boldore, or whether or not you think that Unsho Ishizuka's voice recording has been archived for voice's of Ash's Kingler, Muk, Swellow and Boldore, or whether or not you think that Ash's Kingler, Muk, Swellow and/or Boldore will be written out of script, while is also unknown whether or not you think that any the other original Japanese voice actors and actresses will be available to reprise their original Japanese voice role of all Ash's Pokémon, which other Japanese voice actors and actresses you think will replace them, or whether or not you think that any of Ash's old Pokémon will be written out of script. Why do you think? Please let me know, thanks.