The Digimon Infobox treats any usages of it as an official species which is why using it for Fan Digimon is against the Wikia's Manual of Style:
While Digimon Wiki encourage a healthy fan community, and allows fan fiction, fan art, and discussion of Couplings to be shared with the readers, it is imperative that these are never placed such that a reader confuses them for official materials. Such a thing would be misleading to readers, and so would be treated as vandalism by the admins, and either reverted or deleted.
Additionally, the Fan Digimon Infobox correctly categorizes Fan Digimon as such.
omnimon merciful mode has yet to be "ultra" in an appearance. hes not mentioned as a level in tri (likely mega), and is a mega in links, as ultra doesnt exist. if hes in the next console game, hell prob be ultra, but until then he;s a mega