Cryx Bane Highlight vs Light Brown

How close are they?

ΔE 16.7, loose: different enough that you should pick on purpose. Light Brown is much more saturated, warmer than Cryx Bane Highlight.

Can I use Light Brown instead of Cryx Bane Highlight?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Light Brown is much more saturated, warmer than Cryx Bane Highlight.

Can I use Cryx Bane Highlight instead of Light Brown?

The same difference applies the other way round: Cryx Bane Highlight is much 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.