Can I send a project from my MacBook Air to a friend with a different Apple Account, where they can still edit and access the movie?

An editable iMovie for Mac project cannot be sent independently to another person. An iMovie project must reside in an iMovie library. iMovie Libraries cannot be stored in the cloud, so you can't use the cloud. You can place the iMovie Library that contains the project onto a drive or thumb drive that is formatted Mac OS Extended (Journaled). Then you can send the drive with the library that contains the project to your friend, and he/she can edit the project and send the drive back to you. Each time you send the library you first should do a File /Consolidate Library Media to make sure that the library carries with it all media used in the project. You friend must have a Mac computer (not any other device) and be running the exact same version of iMovie that was used to create the project.

Easiest to create a brand new library that contains only this one project. Also, best not to do any updating until the project is completed.

-- Rich

Yes.

If you directly send it to them, that would be their own copy to do with as they please, and their edits would not effect your copy.

If you decide to share on iCloud, then you will be given an option to change what they are allowed to do. Any edits completed by either of you would effect both copies.

I hope I was of some help.

Cheers,

Jack