the first one you can see some Vilemon with Devidramon and SkullSatanmon, in the second one There are 4 differents digimon behind Ghoulmon: Devidramon Vilemon SkullSatanmon and I think this one is Mephistomon
Mephistomon's horns are significantly larger (nearly the size of its wings, which are themselves pretty small compared to its limbs), and its tail is tufted like a goat's, and not nearly as long as its legs. The previous scenes also have 2 silhouettes each for what have to be Boogiemon and Devidramon, so just because there's four silhouettes doesn't mean there's four species.
The proportions don't make sense to me to be Mephismon, and Mephismon would be pretty unusual, thematically, as a generic footsoldier for a demon army. It's usually depicted as more of an individual.