Cadian Fleshtone vs Elven Flesh

How close are they?

ΔE 19.3, loose: different enough that you should pick on purpose. Elven Flesh is noticeably lighter, more saturated than Cadian Fleshtone.

Can I use Elven Flesh instead of Cadian Fleshtone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Elven Flesh is noticeably lighter, more saturated than Cadian Fleshtone.

Can I use Cadian Fleshtone instead of Elven Flesh?

The same difference applies the other way round: Cadian Fleshtone is noticeably darker, 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.