If you take it so, then:P. DelSlayer said:They go for themes within the Eeveelutions, then take the best types for those themes. (well, mainly -Psychic and the sun?)
Actually, Ghost could be a great contrast to Sylveon. Especially with the implied life/death theme.
Sylveon = fairy, full of life etc (basically a mini Xerneas but without Xerneas powers)
Ghosteon = dead, spectral etc.
Just a possibility.
Sylveon = “the cute one, playful, safe”
Metaleon = “the serious one, the “fighter”, dangerous”
If we get a ghost one, then, it'd be another one Umbreon would be strong against, wow! I knew, why I like “Umbrie” the most.