Titles, Designations, and rituals: In the vernacular or in English?

One of the problems with all the research I did before writing 'Asoka' was with the titles and other names to be used in the books. I'm referring to these terms: Senapati; Maha amatya; arahant; Nagaraka; Sailandri; Rajpurohita; etc. While usage of these terms lends to the authenticity of the story, adding footnotes for each one of them and an Index at the end would make reading laborious. As a reader immersed in the story - as I would like the reader to be! - I would not want to flip pages looking for footnotes or turn to a bookmarked index to look at the meaning of certain words. This story is being written in English. It would only make sense to use English translations of these terms, thus making them more 'worldly' or 'globalized' as we call them in the technical writing world. 

Now let's substitute the terms used above with English translations: Chief of the army; Prime Minister; monk; City head; attendant; Royal Priest or Priest of the palace. Now even if this would rob the essence of some of the original terms, at least these terms will immediately connect with the reader, especially with a non-Hindi speaking one. It is easier for an English reader to remember these terms instead of trying to recollect each time what each vernacular term means. 

Far as the pronouns are concerned, I need to decide whether I should use the Anglicized versions - with the 'aa' sound at the end - or use the original, vernacular ones. Let's consider this: Girivraja; Pataliputra; and Kalinga; OR Girivraj; Pataliputr; and Kaling;

Even for human beings: Asoka; Sahadeva; and Radhagupta OR Asok; Sahadev; Radhagupt. 

In the case of names, both for places and for humans, I think using the vernacular ones is a better option. The distinction between the two Asoks will have to be clear. The prince or king is always Prince Asok or Prince; or Great King Asok or Samrat Asok. I like the idea of using 'Samrat' too. It adds to the authenticity and also helps creating a distinction between the two Asoks, especially when both are present in a scene. 

In the case of 'Aggamahesi', which is 'Chief Queen', I will use the vernacular term as pronoun for Sushim's mother. I've searched all over for her real name, but I could not find it anywhere. Unless I find it before I finish the book, I will use Aggamahesi as the Queen's name.