The Zero Two poster strikes as kind of weird. I can accept the idea of a teaser poster being done in a sketch style, but the whole concept just seems a bit off.
Like, in the original Adventure continuity we pretty much know that none of the Zero Two kids had anything to do with any chosen predating the adventure kids, their backgrounds are pretty definitely known. I don't see what the point would be to retcon the crap out of their history just to introduce some new character that no one's probably going to care about after this movie. Yet, without a connection to those characters there's like no point in this being Zero Two branded rather than just Adventure.
What would make sense from the perspective of a setting would be that the movie could outline the background of those characters in the Adventure: continuity but that does not fit with the poster at all; The style of the text and the logo very much ties in with the aesthetics of Tri and Kizuna and not with the much more bold style of the reboot. So that's a weird one.
So anyway, If I had to choose between one of the two the Ghost Games one is definitely more convincing. I mean just based on the title alone... "Ghost Games". It's just seems so vague and random that it's not really something a fan would invent with the intention of seeming legit. Fan fakes will often try to seem more official by piggybacking very literally on preexisting stuff, and emulate previous naming conventions, but when you have something that just kind of comes out of left field... that has my attention.
The poster looks fine overall.
None of the protagonists seem super young for Digimon standards so there's at least a chance that it's not aimed at literal toddlers like Appmon was.
The stringy CLAMP style legs might take a bit to get used to but at this point you take any stylistic innovation you get. Speaking of innovations it kind of looks like the jellyfish fairy is paired with the white haired boy and not with the girl.
There doesn't seem to be much to unpack about the concept of the anime yet, the mention of holograms makes me think that there could be some AR element to the story maybe similar to Dennou Coil.
That said, if the ghost part is meant literally in the sense being one of those settings that claims that Digimon are not actually digital and inserts some generic drivel about spirits I am going to turn in my grave and I'm not even dead.
Anyway onto the Digimon designs:
The little triceratops guy looks fine. Honestly a really nice way to have your classical dinosaur/dragon protagonist but not based on a generic carnivore this time.
The fairy girl thingy... a bit too much of a chibi but at least there are very non-human aspects in her design and she retains those classic Lilymon fairy eyes so... pretty much acceptable.
But the big fur monster... holy shit. This has to be one of the worst Digimon designs I've ever seen. Nothing about this guy fits with any aesthetic the franchise has ever used. He just looks flat. The utter lack of detail, the weird egg shaped torso, the angular arms and hands with not a single visible joint, this thing looks like he crawled out of some early 2000s Nickelodeon cartoon made with flash.
Whoever designed this had literally no idea what makes a Digimon design work. All they seemed to know was that Digimon sometimes have belts on them but completely missed the point that those belts usually serve in a Digimon's design: Purposeful irregularities. If you look at basically any Digimon that uses Belts as as an accessory and not in a practical utility you'll notice a very intentional lack of symmetry. There's either going to be only belts on one arm or leg or the belts around different body parts are distributed, or spaced differently, simply used excessively, or cross the body at an angle to create a sense of dissonance. That's always the key, to visually throw the design off balance and give it more dynamic look. Here there's just a single belt on each arm and it just makes him awkwardly look like he's carrying a backpack.
If this turns out to be fake I would at least be happy to not have him as a part of the franchise.
On a more general note I kind of feel like the believability of Ghost Games kind of boosts the believability of the Zero Two poster since they seemed to have surfaced together and both have the same kind of downscaling artifacts which points towards a common source. Not a bullet proof connection since terrible downscaling is pretty common but I still think either both are fake or both will be real.
What if the 02 movie kid is Iori's dad, Hiroki?
Then we'd be looking at a worst case scenario. Besides looking nothing like Hiroki, we know that even up to high school age neither Hiroki nor Oikawa actually knew that Digimon were actually real. They never had more than a hunch and that was an important point. Part of Oikawa's grief was that
he was the one who found out that the digital world was real but Hiroki died before he could tell him. And it would make zero sense for Hiroki to have a Digimon partner and keep it from Oikawa since they were best friends at the time and only started to drift apart around the time Hiroki went to college.
Oikawa might not be the most iconic characters but he was one the very few characters in Zero Two with a decent backstory that they would absolutely trample on in that case.
If this is real, is very contradictory to the Bandai product tease that suggested an Adventure: continuation. Unless that one referred to the 02 movie.
It's not really a contradiction as it would be a continuation of the Digimon Anime in general. They never talked about a "sequel".