Pastel Seafoam vs Spectral Wolf

How close are they?

ΔE 29.3, loose: different enough that you should pick on purpose. Spectral Wolf is noticeably darker, more muted than Pastel Seafoam.

Can I use Spectral Wolf instead of Pastel Seafoam?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Spectral Wolf is noticeably darker, more muted than Pastel Seafoam.

Can I use Pastel Seafoam instead of Spectral Wolf?

The same difference applies the other way round: Pastel Seafoam is noticeably lighter, 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.