ΔE 15.0, fair: the same colour family, but not a straight swap. Plague Brown is a little darker, much more muted than Moonbeam Yellow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Plague Brown is a little darker, much more muted than Moonbeam Yellow.
The same difference applies the other way round: Moonbeam Yellow is a little lighter, much more saturated.
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 Moonbeam Yellow on the colour wheel See Plague Brown on the colour wheel
All matches: Moonbeam Yellow equivalents · Plague Brown equivalents