I loved this chapter. With the fighting type I think you made a good choice, obviously... just one thing...
Could you make it so Stitch has two types (fighting plus something weak to massive amounts of water?) plus some ability that lets him have a third type that resists the type of the last attack he endured (I know having three types doesn't happen in Pokémon, at least the main games and anime, but I feel with Stitch's incomplete nature that let him develop Pokémon abilities after that thunderbolt he should get some special ability that lets him adapt)?

As for entering canon events... I think Lilo wouldn't be that happy about making Stitch fight for sport, maybe to become strong, but not to "boast" like when trying to get the Gyms and all that, so I think she would maybe do/change some canon events but wouldn't participate in those directly related to the League (of course exploring Kanto or working with Professor Oak is feasible), so I'm excited about getting into canon events but not that much.

Also, with the events of this chapter, you can add more, unexpected events to the Pokémon chapters by having not only Jessie, James and Meowth looking for Ash's Pikachu (if that ever happens) but another group from these Grunts who raided the ranch searching for Stitch/revenge?.

Awsome story can't wait to see more wonder how jumba and the others will feel also i remver a story were the experimentz had pokemon dna in them and could be captured in a pokeball can't wait to see how you handle things

You know... you could make it so Stitch can evolve as the story goes if you play it right, and if you don’t want to do that, you can give Stitch an ability that changes his typing, like Geninja and Sorbunny’s hidden abilities, or even Arecus or Silvaly.

It would be cool to see a dragon type Stitch, Ice Type, etc

Also will Lilo catch any Pokémon? And will any or Stitch’s cousins appear thru the story?

I am excited to see what happens next

Yeah I can see him as a Fighting type if my memories of the show are right, so Stich will tease a lot Lilo of Ash being her boyfriend? Well not boyfriend boy eh best friend? Eh I don't known, also will Ash catch all of his Canon pokemon or he will gain new ones? I hope he get an Eevee! or Lilo, I don't care who get it, Im just hoping for an eevee, their are so cute!

Excited to see what happens next, fic has tons of potential.

Only problem I have is how hoopa talks... hoopa talks more like this

Hoopa: baali hoopa ring, Ash-kan, Pi-kan

Watch the Hoopa movie to get a better read of how he talks in both his forms, but other than that the story is great so far, keep it up!

OK so where's is this ubicated? Before the anime begins? And what king of relationship Ash and Lilo will have? It would be hilarious if she ended in Alola, seeing that the Region show a lot similarities with Hawaii