With the finding of the emigration pass from India to Fiji, we now know the village/town that one great-grandfather is from. The name is Domariyaganj, then from there is a smaller village of Prasahwa. On these maps, from the 1800's you can see Basti (or Bustee), and Domariyaganj (with various spellings). Also, in his travels my husband has met other Indians, one of whom is from that area and may know someone in those villages who can find out some info for us.
Enjoy the maps! (click to view larger)