Theoretically, if the Sun Bears are to be phased out too; that would give them four reasonably sized enclosures within close proximity of each other which would essentially allow for a rotational system to be implemented for Sri Lankan Leopards and Sumatran Tigers.Sri Lankan leopard would be ideal as they’re not subject to the issues associated with housing small felids near apex predators. This would all be negated by housing orangutan adjacent; but your idea of Sri Lankan leopard would make more efficient use of a larger space.
Sri Lankan leopard could also rotate with the tigers theoretically, unless that’s to be designated to expanding tiger holdings.

