Since there's not much information given, they could be original characters created specifically for this fanfiction. They might be two individuals that the fanfiction writer has imagined, with their own unique personalities and backstories that are explored within the story.
You can try fanfiction websites like Archive of Our Own. It has a large collection of various fanfictions, and there's a good chance you'll find some great lilo paynlinson fanfiction there.
Some forums dedicated to Disney or 'lilo and stitch' in particular might also have fanfiction. For example, there could be a section on a Disney fan forum where fans share their own 'lilo and stitch' stories. You might need to register on these forums to access all the content, but it can be worth it to find some unique fan - made tales.
An unexpected event can also be a catalyst for their relationship development. Such as getting lost on an island adventure. During this time, they rely on each other for survival, and in the process, they discover new aspects of each other that they find attractive. This could lead to the realization of their love for one another.
You can start by looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms usually have a wide variety of fanfiction, and you can use the search function to specifically look for Lilo and Stitch Pokemon crossovers.
The back story of Lilo and Stitch involves Stitch being an illegal genetic experiment created by Jumba Jookiba. He was designed to be a destructive force. Stitch escapes and ends up on Earth in Hawaii where he meets Lilo, a lonely girl. Lilo is dealing with the loss of her parents and is a bit of an outcast. Their meeting sets off a series of events where they form an unlikely bond and Stitch starts to learn about 'ohana, which means family in Hawaiian. Their relationship grows as they face challenges together, like dealing with the alien hunters who are after Stitch.
In lilo experiment time travel fanfiction, the character Lilo might embark on an adventure through time. Maybe she travels back to a crucial moment in her planet's history to prevent a disaster. For example, she could go back to when some ancient technology was lost and ensure it is preserved, thus changing the future for the better.
One great 'Lilo & Stitch' fanfiction is 'Stitch's New Adventure'. It takes the characters on a journey to a new planet where they encounter strange and friendly aliens. The author does a wonderful job of keeping the spirit of the original show, with Stitch getting into all sorts of comical and heart - warming situations.
There's also a fanfiction where Lilo and Stitch time - travel. They end up in the future and have to deal with advanced technology while still being their unique selves. It's really interesting as it combines the charm of the original characters with a futuristic setting. In this story, Stitch's adaptability is put to the test in a whole new way.