If you are asking if someone time travel from one timeline/universe is creating the other ones (timelines) or they are already separated from the beginning (universes), then, universes.
It is a Greg Weisman thing. Apparently at some point an Atlantis: The Lost Empire series was in development and he wrote an episode that was going to be canon to Gargoyles. NOT making Gargoyles and Atlantis the same universe, but that the episode was canon to Gargoyles and Atlantis...
They could always explain that, maybe some day they could release a series about the avengers of this universe and show in the first episode (I know is not going to happen, shut up, let me dream).
Also you still haven't added this:
https://www.thecomicboard.com/threads/id-software-shared-multiverse-timelines-playing-orders-wip.14997/
https://www.thecomicboard.com/threads/gundam-timelines-viewing-orders-wip.14937/...
Could you rename "Lilo & Stitch" to "Disney Channel Animated Shared Universe"? (And move it to an earlier point, since now it would have begin with Recess instead of Lilo & Stitch)
It seems that there is at least 7 universes in this "cluster":
Earth-21913 (Next-Gen version)
Spider-Man (Xbox)
Spider-Man 2 (PS2/Xbox/GameCube)
Spider-Man 3 (PS3/Xbox 360)
Earth-???? (GBA version)
Spider-Man (GBA)
Spider-Man 2 (GBA)
Spider-Man 3 (GBA)
Earth-???? (DS version)
Spider-Man (GBA)...
The Marvel Database has given TRN1176 to the PC version of Spider-Man 2 and TRN1177 to the GBA version.
They should probably give one to the PSP version, another to the DS version and another one to the N-Gage version.
Ok, now there is a source in the page in Marvel Database of Earth-21913.
The page of the Appendix for Earth-616's Dr. Shannon Stillwell (sister of Dr. Farley Stillwell, creator of Scorpion) list Dr. Stillwell from the Spider-Man 3 video game (creator of Scorpion in that universe) as an alternate...
It was just a Taxi Driver remake but with the names "Gotham City", "Arkham Asylum", "Thomas Wayne", "Bruce Wayne", "Martha Wayne", "Alfred" and "Joker" slapped on it.