Ochre Clay vs Ironjawz Yellow

How close are they?

ΔE 19.1, loose: different enough that you should pick on purpose. Ironjawz Yellow is noticeably lighter, much more saturated than Ochre Clay.

Can I use Ironjawz Yellow instead of Ochre Clay?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Ironjawz Yellow is noticeably lighter, much more saturated than Ochre Clay.

Can I use Ochre Clay instead of Ironjawz Yellow?

The same difference applies the other way round: Ochre Clay is noticeably darker, much more muted.

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.