ITunes downloaded music not available on IMovies.

That's correct. Files that are DRM (Digital Rights Management) protected cannot be used in iMovie. For the most part, DRM protected file were those purchased from iTunes before year 2009. Also, Apple Music is all DRM protected and cannot be used in iMovie even if downloaded to iTunes. Any song purchased where Apple Music was involved in the chain of purchase will be DRM protected even if downloaded to iTunes.

Probably the easiest way around this is to purchase a song directly from iTunes when you want to use it in an iMovie project.

-- Rich

You are very welcome. :)

-- Rich