Spread across the two stages of the trip, last chance species (some of which may already be gone now, or which may be gone by the time I reach the respective collections) include:
Eastern Gorilla at Antwerp; Cacomistle, White-bearded Wildebeest and Screaming Piha at Arnhem; Spectral Tarsier and Spotted Cuscus at Ouwehands
I can confirm that as of the time of writing none of these have disappeared