Here is a summary of the meetings and gatherings scheduled among the characters:

1. Mei and Andy are meeting under the oak tree at the park on Monday, 2 PM to discuss AI project collaboration.

2. Samantha and Noor are meeting under the oak tree at the town hall next Thursday, 2 PM for an AI project update. They plan to meet every other day at the same time there until their project is complete.

3. Andy and Samantha will have a routine gathering under the oak tree every other day at 2 PM at the park.

4. Diego and Leo are meeting under the oak tree at the town hall on Tuesday, 1 PM for a brainstorming session. They plan to share tea and possibly music during their discussion.

5. Peter, Diego, and Noor will meet next week, Thursday at 3 PM under the oak tree to discuss their AI project progress, with Peter joining as suggested by Noor.

6. Samantha will catch up with Leo on Wednesday, around 10 AM at the cafe near the library. They'll bring treats for neighborhood strays during their meeting.

7. Andy and Leo are planning to have coffee after their gathering under the oak tree next Tuesday, details yet to be determined.

8. It was mentioned that there will be a solo gallery show by Andy, but no specific dates or locations were provided.