Pretty exhaustive list, Labrokratis! There are still a few other productions you can add:
Mirror of Arei: The Way to the Virgin Space (1985)
This was a special short movie Toei made for Expo '85. It was released on video tape and the Japanese-exclusive disc format VHD, but never on LD.
Saint-Elmo: Apostle of Light (1986)
A TV movie made to promote an electricity company of all things, this was also released on video tape, but not LD.
Submarine Super 99 (2004)
One of the newest unlicensed (in English) Matsumoto TV shows, this 13-part series was released on DVD in Japan, and was also given a French DVD release complete with French subtitles.
The same I feel for the Captain Harlock movie Arcadia of my youth. But that one is licenced I think (pitty: That amazing masterpiece with remastered audio would be a great honor to Leiji Matsumoto and all his fans around the world!).
Arcadia of My Youth was licensed by AnimEigo, but I believe that lapsed a while ago. Indeed some of the other previously officially-licensed Matsumoto material is now unlicensed, such as
Maetel Legend and
Harlock Saga both from the defunct CPM.
DNA Sights 999.9 was licensed by Urban Vision, but in their case it obviously goes without saying that they never released it on DVD.
Second in mind, it comes the Yamato Universe. I know that it is licenced (both movies and series), but there is also that one unlicenced telemovie of the first series that exists and fits perfectly to the Leijiniverse (it doesn’t mess with the Kodai timeline, so you can follow the logic that he became the first Captain Harlock, as it happens in the well known manga...). Maybe that rare telemovie, would be of some interest for your team.
I'm not entirely certain what you're referring to with a TV movie of the first Yamato series, but I suspect it was the specially-prepared version that was mostly the same as the theatrical movie, except with shorter, newly-animated ending. This new ending was included as an extra on one of the R1 Voyager Entertainment DVDs.
I can think of at least one other off the top of my head which I am somewhat interested in (mainly because I know so little about it)... Marine Snow no Densetsu. Maybe sometime in the next few years we'll be able to track down a raw for it or something...
The Legend of Marine Snow, like some of the other older Matsumoto specials, was released on Japanese VHS, but no other format, so raws would technically be available, but obviously not in the best condition.
All in all, I think that covers most of the missing gaps in terms of what other Leiji Matsumoto material is out there, but I wouldn't be surprised if there was even more obscure material just waiting to be unearthed!