Renaming ArcGIS Pro project, APRX, file geodatabase and toolbox?

The ArcGIS Pro Documentation has a page Change project settings which outlines what you can and can't do with your project once it's created.

That said, I did some testing, originally based on the steps you mention in your question. I managed to fully rename my project:

  • Project Folder
  • .aprx
  • Default Geodatabase
  • Default Toolbox
  • Additional File Geodatabase
  • Enterprise GDB connection left as-is

There was a number of steps involved, but it could probably be scripted using arcpy without too much effort. Here's what I did.

  1. Made a new test project called ExampleProject (ie your TestProject) which contained three maps, one layout (with map frames from the three maps), Default GDB, extra FGDB, Enterprise GDB connection, Default Toolbox including two models. The maps used data from all three databases.

    enter image description here

    Note these are named according to the original project - ExampleProject.tbx, ExampleProject.gdb etc.

    enter image description here

  2. Closed my four tabs (three maps and one layout) to remove locks

  3. Saved and closed ArcGIS Pro
  4. In Explorer I renamed the folder and the .aprx to my new Project name: ProperProject

    enter image description here

  5. Double-clicked on ProperProject.aprx to open the newly renamed project in ArcGIS Pro

  6. In the ArcGIS Pro project pane, Right-click > Rename the two Geodatabases

  7. Right-click > Rename the Folder connection, which was still aliased to ExampleProject even though it referenced the correct renamed folder.

    enter image description here

  8. Right-click on ExampleProject.tbx and select Properties. Renamed Toolbox in the properties dialog

    enter image description here

  9. Reopened my Map tabs and corrected any broken layer links, due to the renamed Geodatabases. (I thought the first time I tested that I only had to fix broken links to the extra FGDB but on my second run, for screenshots, I had to do the Default GDB as well, so maybe I was mistaken first time through)

    enter image description here

  10. Save my ArcGIS Pro project.

My project has now been completely renamed. I could not find any reference to my original project. The Layout showed the map frames from the three maps as per how they were originally set up.

enter image description here

enter image description here

As I say, it could possibly be scripted fairly easily, which could be useful for future project renames as required.