This lineup is basically perfect, I’d just trade out the guanaco for something else. Grey crowned crane, Patagonian mara, a coatimundi species, or if a “clone” is a must, black rhino would all suit me better.For grassland (if that's what we're getting), I'd go with:
Armadillo sp. (since that's all but confirmed, though it wouldn't be my choice)
Guanaco
Emu
A macropod (lots of choices but probably red-necked wallaby)
Echidna
Hamadryas baboon or grey langur
Crested porcupine
Not sure of what exhibit animal - maybe a cobra
Agreed that the armadillo is likely to be the weak link, unfortunately.