Resurrection Flesh vs Ochre Brown

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Ochre Brown is noticeably darker, more saturated, cooler than Resurrection Flesh.

Can I use Ochre Brown instead of Resurrection Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Ochre Brown is noticeably darker, more saturated, cooler than Resurrection Flesh.

Can I use Resurrection Flesh instead of Ochre Brown?

The same difference applies the other way round: Resurrection Flesh is noticeably lighter, more muted, warmer.

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.