stealth_nsk
Deity
I don't really see an attractive reason to not spread your own religion. Your own Follower belief is cherry picked to suit your needs. Any others you get are what other people picked. They might be okay, but not as good as the advantages of your own religion which is hand tailored.
In the end I think we'll see minimal spreading of rival religions in India. It's useful if a rival grabs a follower belief you really needed. But the cost of spreading it is (seemingly) pretty high for the bonuses it gives, and doing it makes it easier for those rivals to chase religious victory. Unless there are additional advantages to having multiple faiths I don't forsee a lot of it happening. Maybe the most prevalent case would be aggressive India seizing foreign lands and layering their own religion on top of the pre-existing one.
If you play as India it may be a good idea to choose Founder bonus which doesn't drop if you get not that many followers or some of you cities convert to other religions. Like Papal Primacy, Holy Order, etc.
If you plan to have only minimal representation of other religions, they'll be constantly washed away by your own religion pressure due to amount of followers and nearby Holy City. To keep maximum religion diversity (and thus maximum bonuses) you need to invite strong religious pressure and maybe even have a reserve of different religion missionaries to fix any imbalances.