I've seen and heard all of the (available) general information about the Space World G/S prototypes and I'm always interested in knowing more. Man, if I could get my hands on a copy of one of those carts somehow...
Unfortunately, I haven't heard any new information on these prototypes in a long time. Bulbapedia's article
has some pictures of the scrapped Pokemon (though I see you've done some work on Bulbapedia before so I bet you've already seen this!)... but the most unfortunate thing, to me, is that there are no screenshots (well... photos, to be more accurate) anywhere of the demo, so no sprites of those starters or anything.
I've also heard some other pretty wacky info about the demo, such as really strange wild Pokemon (I can't remember the exacts, but DEFINITELY not what you'd encounter that early in the game!) and I also heard the starters were a higher level in the demo... I think 9 or 10? I also recall hearing that "Chikorita" had a move named "Serene" or something as well? Wonder what that could have been!
According to that Bulbapedia page, Kurusu's Pokedex number was also 212, which is... bizarre.
Oh, also, I translated those names in your post, and I got (this is all assuming Google Translate isn't failing me here):
アクア = Aqua
アクエリア = Aquaria
アニモン = Animon (what)
エレキング = Eleking (Elekid? Or maybe Electivire was planned for G/S too? :S)
ハネコ = Haneko (no idea--- oh it's hoppip apparently)
イカリ = Ikari
ペインター = Painter (99% sure this would be Smeargle)
プクー = "Puku" this one is perhaps that Qwilfish prototype
サニー = Sonny (... well, apparently Sunflora was "Sunny", so maybe this is just a translate fail)
ヨロイドリ = Yoroidori
Phew! That was a long post with... actually little substance, I'm sorry, haha, you've probably seen/heard about most of what I talked about already. I feel like a lot of things surrounding the G/S development are actually kind of mysterious, which makes me like it even more.
So, overall, I'd say it's fairly obscure. If you find any more/new info, I'd be really excited to hear about it. Sadly I don't understand any Japanese, so I can't read those pages.