After the Gurkhas become the mercenaries they are supposed to be, the Indians will need new skirmishers.
This means that changes to the Indian civ’s unit roster will theoretically not affect the civ’s requirement for two firearm infantry.
Sepoys (musketeers) and Banduqchis (skirmishers) will both be on the new roster.
This is exactly the idea I have in my indian units concept.
Truth.
For me, mercenaries are a very convenient mechanic to introduce new things that cannot be used as units in existing civs and minor civs, such as the Swedish Fusiliers and the Italian Elmeti in the past.