Added a #4 tool to my original post above. Anyone have any experience using Wondershare? I will try to look at it this weekend.
Wondershare Video Converter Ultimate (MKV, MP4)
Searches online sources for data. I have not looked at this program personally so I cannot vouch for its reliability but perhaps someone else can comment on that.
I also added an
article link to Tweaking4All that indicates that VLC's media tab also supports add/edit metadata.