In terms of other island endemics ZSEA have the Sri Lankan leopard subspecies and if Australia is included under "islands" rather than as a continent then ZSEA gain the red kangaroo.
In terms of the Aspinall parks if the South-East Asian islands are included then they gain a carnivore, a bovid, and a number of Old world monkeys and Lesser apes such as : the Sumatran riger, Sulawesi macaque, Javan gibbon, siamang, Javan gibbon, fishing cat, lowland anoa etc (if Australia is included then the Aspinall parks gain a marsupial too, the Bennett's wallaby).
With birds, reptiles, amphibians and inverts (due to the focus of the Aspinall parks on mammals) things move towards being in ZSEA's favour in terms of species kept.
Birds : Bali starling (If Australia, New Zealand, Papua New Guinea are included under "islands" then this is boosted by boobook owl, Ducorp's cockatoo, emu, galah, kookaburra, sulphur crested cockatoo and Swainson's lorikeet).
Reptiles: Rhinoceros iguana.
Inverts: Halloween hissing cockroach, New guinea spiny stick insect, Madagascan hissing cockroach.
In terms of conservation, ZSEA apparently does no direct conservation in-situ work and so again the Aspinall foundation comes out on top. I personally voted in favour of the Aspinall foundation because of its conservation work in Madagascar and ex-situ work with lemurs which is more significant to me than the range of species kept by ZSEA.