Err...
Sikhism developed under pretty specific conditions. It derived from the specific pressures and societal tensions between Islam and North Indian Hinduism. It took root in the Punjab specifically because this was a heartland of the Mughal empire with the consequent social and political interplay between Islam and Hinduism magnified.
The religious, cultural, and social dynamics on Ceylon were and are totally different. For one thing Islam is very much a minor religion there in comparison to Buddhism and Hinduism.
I mean you could have a charismatic religious syncreticist arise in Ceylon but he's going to have a totally different background to syncreticise from.
