I think "Indian savanna" is used in this ranking system to mean all the grassland as well as tropical dry and tropical moist forest habitats of India that share a similar roster of relevant animals. Gaurs are very much found in the terai savannas, tropical dry deciduous forests of the Deccan and Central India, and montane grasslands in the Western Ghats, in addition to their more moist and evergreen forest habitats in India. So definitely work here. In fact, the lion-tailed macaque is the species that is most partial to the "forest" over "savanna" but would perfectly fit the region as defined here.Gaur (technically lives in forests but whatever)
Sub-Himalayan India is really what the region represents. TBH even some of the regions of northern India that are depicted as part of "tropical SE Asia" on the map are too far west to count. Basically southern Nepal and the adjoining northern areas of India - the species roster there is Indian rhino, blackbuck, barasingha, etc. as opposed to the binturongs, sun bears, etc. that you get further east beyond Assam.