Tranferring an iMovie project from iPhone to MacBook Pro
Turns out I finally found my own solution:

Make sure you have the latest versions of iMovie, especially on iOS. This was the main problem causer for me, as iMovie claimed to be updated and would not show up in the updates in the App Store until I restarted several times.

From your iPhone: export the project you wish to transfer to iTunes. Connect your iPhone to your computer via a USB cable and download the filename.iMovieMobile file to your computer.

Open iMovie on your computer, and click File &gt; Import iMovie iOS Projects....

You should have the project imported to iMovie on the computer! Now, you can even transfer to Final Cut Pro X (see here for info on how to do that).

Make sure you are running the most recent versions of iMovie!