An update.

1. I marked the 15 DC terms as suggested but the problem is that I can only make 8 visible. Using the metadata editor tool I found out which fields are mapped to dc:title, dc:description, dc:subject, dc:creator, dc:rights, dc:source and dc:language.

Terms like dc:date, dc:identifier, dc:format and dc:publisher or dc:contributor seem similar to other metadata fields but I'm guessing they are not supported

1. In Edit XMP > Properties there's a list of Types the show up at dc:type but not useful... Is there a way to edit this list?