ΔE 16.3, loose: different enough that you should pick on purpose. Succubus Skin is noticeably lighter, more saturated than Umber Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Succubus Skin is noticeably lighter, more saturated than Umber Brown.
The same difference applies the other way round: Umber Brown 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.
See Umber Brown on the colour wheel See Succubus Skin on the colour wheel
All matches: Umber Brown equivalents · Succubus Skin equivalents