I can only answer the last part. Unfortunately, while the team desires kudos for the jplayer plugin, the upload instructions are (shall we say) lacking...

The only way I've figured out how to get it to work is to manually upload the photos to to a Gallery directory (that is, a sub directory under the galleries directory). something like \var\www\piwigo\galleries\movies.

Once you do that you can go into the admin screen and hit the synchronise button to pull it in. Moving the resulting movies from one gallery to another is still flakey, but at least it shows them.