For the record, no where in the official epub3 spec that I could see does it say you should add a manifest property for something not inside the epub3 container. I realize that many people/sites say you should add a manifest item for remote resources but I could not find it in the spec anyplace. If someone can send a link to where in the spec it says it should be that way, I would love to see it. A manifest by its very nature should only include things that are actually contained there-in.
So what happens if you remove the manifest items such as these:
Code:
<item id="vid2" href="https://www.website.ext/videofile2.mp4" media-type="video/quicktime"/>
but keep the remote-resources properties on the xhtml files with source links to external resources?