ΔE 28.1, loose: different enough that you should pick on purpose. Squid Pink is a little lighter, much more saturated than WWI German Lilac.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Squid Pink is a little lighter, much more saturated than WWI German Lilac.
The same difference applies the other way round: WWI German Lilac is a little 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.
See WWI German Lilac on the colour wheel See Squid Pink on the colour wheel
All matches: WWI German Lilac equivalents · Squid Pink equivalents