I am not happy about such ideas and usually don't use explicit words on HN but this startup is a bit off for a YC startup. It's surprising that a well-known fund invests in such a venture.
Why do you want to keep people from specific religions stick together? It's for a society always better if groups mix instead of a ghettoization. I know that still many try to stay with their people which is totally fine but why enforcing it? You write yourself that there is a strong 'religious pressure'. With your product you make this pressure even worse. Oh I have to find someody of my religion and skin color, everything else is forbidden. It's not, it's 2017.
It's just not right. Imagine I make tomorrow a dating app for white Christians. Just with this description, I exclude other religions and skin colors and probably imply that those folks are inferior, you get it?
The biggest issue that all people who look like your target demo suffer from these stereotypes you create and enforce. Oh look at this dark skin guy, he probably looks for a wife wearing a headscarf 24/7, doesn't eat pork and prays on a carpet five times a day. Nothing bad about this lifestyle, it's a totally fine way of living which I respect, but please do not create stereotypes. There are many of your target demo who are happily fine to marry someone not from their religion.
And dating as a business is super though (eg banned by FB Ads) and since Tinder almost impossible. Unsure about your growth potential. Religous folks still use traditional ways (parents and co) and the other use traditional dating apps.
And2: Paul himself wrote himself many times, do not do dating. Why does YC still do dating?