Morghast Bone vs Light Orange

How close are they?

ΔE 16.5, loose: different enough that you should pick on purpose. Light Orange is noticeably lighter, warmer than Morghast Bone.

Can I use Light Orange instead of Morghast Bone?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Light Orange is noticeably lighter, warmer than Morghast Bone.

Can I use Morghast Bone instead of Light Orange?

The same difference applies the other way round: Morghast Bone is noticeably darker, cooler.

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.