Before anything let me just get this out the way...
Nick Robinson as Ash Ketchum/Satoshi/Red
For every fancast I've visited I've seen Ash Ketchum (the [frick]ing iconic 10 year old that never ages) be (in theory) played by a grown man. Not just a grown man but a really really grown man. Obviously casting a 10 year old in the role isn't the best option so I opted for a talented actor in Nick Robinson. If the producers feel Ash is too iconic to touch or feel people will have trouble keeping the movie universe separate then they can just rename him and keep him as the main character (hence the reason I tacked on the Red in the name part) You know what I'm talkin about gamers! If you watched The Kings of Summer then you know Robinson has great charisma and amazing comedic timing to his credit.
Karen Gillan as Misty
Gillan is at the top of her game right now seemingly getting offered and rumored for many movie roles. Gillan is my number one pick for Misty as she already played a femme fatale in GOTG. This time she can play an actual human though and be the main source of feminine power within the group as she is known for.
Brandon Smith as Brock
Coming off his critical acclaim for his portrayal of Little Richard in the film Get On Up, Brandon Smith is the perfect choice to play the brains of the trio and also charismatic enough to be the guy who falls for every woman he meets. Brock is a central character of the series and should be given no less than that treatment in the film.
David Duchovny as Professor Oak
A respected sci-fi actor Duchovny has the look and chops to play a believable Professor Oak in a movie that may or may not include some sci-fi elements to it. Oak is the one who gives Ash/Red his first Pokemon before our young protagonist sets out on his journey.
Tye Sheridan as Gary Oak
Normally when I do these "Nostalgia Fancasts" as I like to call them I see comments like "that kid looks like a douche". This is the one time I agree with the people who make those comments. Tye Sheridan is a talented actor who has appeared in films like Mud but he also has a very unlikeable aura about him which makes him perfect to play the overachieving prodigal Gary Oak.
Naomi Watts as Delia Ketchum
At 46 years old there is no doubt that Naomi probably is and can play someone's mother. She can without a doubt play the mother to our protagonist and also be a strong female character within the film and appear in multiple movies (because let's face it if Pokemon was a hit movie there'll be sequels).
Mary Elizabeth Winstead as Nurse Joy
The gleeful nurse that seemingly has infinite siblings with the same name, Winstead has done some very strange roles in films that aren't guaranteed box-office hits so I think she could definitely see the value in a well-done Pokemon film.
Gemma Arterton as Officer Jenny
This one was a no-brainer as she's clearly very attractive and has proven she can kick ass as she showed us in Hansel and Gretel alongside Hawkeye Jeremy Renner even though it wasn't a necessarily good movie.
Ben Whishaw as James
Being on a roll of acting in some excellent films lately Hollywood thinks Whishaw is good enough to play the legendary Queen frontman Freddie Mercury. I figure if he's preparing to play Freddie Mercury he'll have no problem playing the out-there James of Team Rocket.
Jennifer Love Hewitt as Jessie
If you've seen The Client List then you know Hewitt has the acting ability and knows how to rock some different colored hair for her roles. The ying to James' yang these two could have the chemistry to make up the famous Team Rocket duo. Meowth would just be made into a badass Pokemon so no voice for him. Sorry.
Like my last Nostalgia Fancast for the Mighty Morphin' Power Rangers, if this one is well received I may make a second part in which I cast next-generation and characters I missed such as May, Dawn, Giovanni etc. Hope you enjoyed the fancast.