ΔE 11.6, fair: the same colour family, but not a straight swap. US Earth Yellow is a little darker, more saturated, warmer than Skeleton Legion.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). US Earth Yellow is a little darker, more saturated, warmer than Skeleton Legion.
The same difference applies the other way round: Skeleton Legion is a little lighter, more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Skeleton Legion on the colour wheel See US Earth Yellow on the colour wheel
All matches: Skeleton Legion equivalents · US Earth Yellow equivalents