Eorzea or Etheirys?

[Enkidoh]

Meanwhile, Meracydia has African plants and animals (aloe, sesame, hippos) while Australian animals are not credited to it.

Actually, Aussie animals are credited to Meracydia as well, well, at least one is (the wind-up kangaroo minion description mentions it's based on a "Meracydian marsupial") - whether the Ittybitty Duckbill, Frill-necked Lizard and Koala Joey specifically come from there too also isn't mentioned though (although the koala and duckbill are also seen in Elpis so that means like most of Hydaelyn's modern wildlife the Ancients created them originally -amusingly the minion description for the Koala Joey seems to suggest it's found in Eorzea given it "dropped down onto a retainer who was cutting down it's tree").

Also I understand wattle bark can be found via BTN gathering in Azys Lla (wattle being an Australian native tree of course), and the dragon sector of that was literally lifted wholesale from Meracydia, so it's basically all but proven Meracydia is a "great south land owing more to Australia but has some elements of Africa as well" (it isn't shaped like Australia though, apparently being roughly triangular in shape according to the Hydaelyn model seen from the moon).

I still think Aldenard is roughly Africa in shape, but culturally is more Europe/Middle Eastern than anything. But I digress.