If an enclosure was built at the figtree, on the existing island, the Macaw Aviary, and the Japanese island, and the existing Orangutan/gibbon enclosure complex, I think the lake would not need extending, and a second gorilla exhibit could be built encompassing Man Jai's enclosure, potentially going right up to the lake's shore.
Leaving the Barn and other two elephant paddocks for something else... maybe a planting of Sitka spruce, red cedar, western hemlock, and Pacific silver fir for two Spirit Bears to feel more at home on in the Pacific Northwest...