New- Tinker Bell 2007 (aka Ring of Belief)

The main differences between the project are the creative direction,
voice and character casts, story elements, music etc. Almost every version of the early script includes the same "magic" and design of the Pixie Hollow world with a purple tree. The whole movie changed a whole visually and structurally when Disney bought Pixar and John Lassetter wanted to make changes to the project at Disneytoon studios, known for making sequels. When it was in this phase, many aspects changed such as the fairies' magic. In the original version, they went to the mainland (real world) to bring imagination to children. JL wasn't fond of this idea and preferred fairies to be more naturalistic. Then two versions of the movie were pitched. Sharon Morill pitched a new idea to JL about a trilogy of a romeo and juliet story with a fairy rock band that JL didn't like, so the production recieved a new director (Bradley Raymond). The current version is more naturalistic and the earlier versions visuals were inspired by art noveau, and had more of a whimsical look. The early are also taught at a fairy school known as the conservatory, before they get to spread belief to the world.

In both versions, every fairy friend has their own unique talent. (Light, Water, Garden, Animal, Tinker/Pots and Pans)
However, in the final version there is more emphasis on talent as the fairies bring the seasons to Earth, the mainland. Tinker Bell created a mistake so the fairies couldn't go to the mainland because she felt like she didn't belong as a Tinker who doesn't manipulate nature. This mistake puts spring in danger. In the early version, we see that a grave mistake is made by TB/the fairies that puts all of fairy kind in danger because children aren't believing in them. Additonally, the Peter Pan characters and new human characters were more involved in the story at one point. This was changed to a small cameo of Wendy at the end of the first TB movie who seemed to have the same 3d model as the deleted character, Victoria the orphan, with the face remodeled.

The early version seems to have more inspo from Peter Pan (Disney/original by JM Barrie) while the final uses more from the published fairy books. Both use the talent idea/wording from the book "Fairy Dust and the Quest for the Egg". But they honestly use both and that book does borrow from Barrie's peter pan too. For example, I looked into the neverbird character from the Fawn story clips and found it was a character from the original Peter Pan, not in any other Disney media but a Disney Junior cartoon.

There also seems to be various differences between scripts and versions of the early version.
This version- which seems to be related to the fairies fixing the mistake by going on individual quests throughout the Pixie Hollow world, which is rumored to be segmented like "episodes" and to have 2d animation. It is unknown who the director was or any real details about the people who worked on this (and I'd say that for the other two as well, even with SM having a lot of influence i dont think she was a writer/director- not the main one at least)
Second version- Included Peter Pan characters such as Peter and Hook and had the fairies go to the mainland to spread belief in London, only for magic and the fairies to start to disappear.
Third version- Had a fairy rock band and a story of forbidden love between different groups of fairies. This one has a storyboard and has have some 3d animation found from one of the sequences. It was animated as a bonus dvd or sneak peek material as an approach to marketing a trilogy. It is unknown whethere this trilogy was just 2 movie series following the mainland plot additional movies or a 3 movie series with this plotline. This also supposedly used a French animation studio instead of the Prana studios in India who had worked on the TB project. One of the new characters is named Harmony, but we don't have the names of other new characters from this version.

A good video to see most of the story beats changing is "whatever happened to tinkerbell and the ring of belief?" by Sarah Serif on youtube.

TLDR- Main differences
Plot, characters, script, voices, worldbuilding, influences, staff

Many early aspects are included in marketing/merchandising also.

That might have been me, your archive was incredibly helpful for lost games and artwork. There was this build of a game in called Tink's Pots and Pans jam that had a whole bunch of assets of background characters. I still have them saved, I just have to look for them. If you are interested in discussing this we can do that as well

Anyway, there is one in the blue dress from that game that appears on this documentary- Creating Pixie Hollow at the 8 minute mark and the yellow dress at 7:50.

In the documentary there is a lot of early artwork but it is obviously focused on new the story and the creative influences of the new story. You can kind of see the contrast when the early artwork appears in the doc.