Late to the party but would like to add a few more options to the excellent ones listed above...
(1) The Sikh in the middle of the upper row might work straight out of the "Stalwart Companions" box from Pulp Figures:
(2) I've converted the Wargames Foundry German prisoner standing at attention in their WWI "Interrogation" set to serve as a c.1880 Afghan orderly with a simple head-swap, and the same could be done using an Indian head of your choice:
(3) I've done a similarly simple conversion using a Wargames Foundry Afghan regular artillery crewman with a head-swap from an Afghan regular Infantryman to make an aide-de-camp for Ayub Khan. The converted figure is on the left, with Ayub Khan seated in the middle and appropriately enough the Artizan "Swami" recommended by Drunkendwarf on the right -- again, replace the Afghan fur cap head with an Indian head of your choice: