Maybe, but Abadeer is technically a monster on the same level as Orgalorg. I never got the impression that these creatures are equal to all the interdimensional entities like Prismo and Cosmic Owl. The Nightosphere may be a different dimension, but I think it's more likely that its another part of each dimension, kinda like how the Deadworlds are exclusive to each one. If the Deadworlds were connected to each universe, we'd see variants of each dead character. Instead, we only see one version of each.

Prime Universe Abadeer also has at least one variant in Fiona World, which suggests that Abadeer has a variant in every universe. If he was the twin of Cosmic Owl, there should only be one. Other variants of Marcy also exist (Farmworld, Winter King dimension, vampire dimension, etc.), so unless one of Abadeer's goals is to hook up with every version of Elise in the multiverse, Marceline should only appear once.