Another possibility is that Harry Potter and his friends are on a quest and end up in Tinkerbell's realm. They would be fascinated by the fairies and their way of life. Tinkerbell could help them in their quest by using her ability to fly around unnoticed and gather information. For example, she could spy on the villains and report back to Harry and his friends.
One idea could be that Tinkerbell finds her way into the wizarding world of Harry Potter. Maybe she gets accidentally transported there by some magical mishap. She could use her fairy magic in Hogwarts, like helping to repair broken objects in a more sparkly and unique way compared to the Reparo charm.
Perhaps there could be a magical item that links the two worlds, and both Harry and Tinkerbell are drawn to it. They meet while trying to figure out what this item is and what it can do. They then team up, with Harry using his wizarding skills and Tinkerbell her fairy powers, to unlock the secrets of the item and save both their worlds from a common threat.
The best chapter pointer here is Chapter 13, "Killing the Chicken to Scare the Monkey". It opens with Sensing that something was off with Jiang Yan, Jiang Yan dismissed the... and closes on How could this happen..." Lin Manru didn't want to hear any more of her....
Chapter 907, "Disgusting Clothes", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event. Early on, Zhao Lang originally thought this little kid was just casually saying....
Chapter 926, "Doomsday Beehive Exploded?!", is the clearest early answer because it turns Luo Xingmu's situation into a concrete plot event. The chapter turns that into something concrete by moving from What's this?" Zhao Lang looked at the unimpressive box in his hand...
Chapter 801, "This Elder Sister Is So Smart", is the clearest early answer because it turns Meng Xuezhi's situation into a concrete plot event. Early on, Buchen is quite diligent, he even knows how to tidy up his own.... By the end, He threw down his keys and went straight into the elevator..
Chapter 885, "Isn't This Wine?", is the clearest early answer because it turns Seeing Shuiyun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Daoist Shuiyun's words weighed heavily on Jiang Li's heart like a...
Chapter 934, "Gu Pansheng's Grace [Extras: Protagonist's Edition]", is the clearest early answer because it turns Good Panpan's situation into a concrete plot event. The chapter gives readers a real answer by opening on Twenty minutes later, Jiang Shixu had finished cooking.
Look to Chapter 1 for the clearest answer. It begins with Jiang Li, I'm warning you, don't set your sights on Yinwan anymore, or..., keeps building through Following a bout of tinnitus, she struggled to open her eyes and finally..., and lands on Yet before she had the chance to teach her a lesson.
Chapter 941, "In Which Year Did the River Moon First Shine on People [Extra · River Moon Edition]", is the clearest early answer because it turns People's situation into a concrete plot event.
Look to Chapter 55 for the clearest answer. It begins with Su Yinwan hadn't expected that, in just one day, Jiang Li's reputation had..., keeps building through Yet she was clearly the wretched cannon fodder of this book., and lands on He Yun's fans were immediately displeased..
Chapter 846, "Locked up for 6 months!", is the clearest early answer because it turns Mom's situation into a concrete plot event. It opens with She took a deep breath, and a guilty expression immediately appeared...