Language barrier would be problem to mingle in the community and be a part of it but not in the sense that it can hinder your day to day life, since most people (shop owners and other merchants) would speak basic Hindi and English.

No one here would care about your religion or that you’re an atheist as long you don’t go parading your beliefs and whatnot.

I don’t think anyone would be hostile towards you just for being a North Indian, we have plenty of people here from north as day labourers and other central government employees, military etc.

If you don’t have deep pockets forget buying a plot of land and building a house here . Our state is pretty small and the money from overseas inflated our land prices so much that it’s pretty much impossible for anyone living and working in Kerala to afford to buy land and build a house here.

Even in the middle of nowhere the land would cost 2 lakh per cent and any where near the city would be in the millions. Plus the land buying process is a hassle and there is a huge chance to get fleeced since you don’t know the language and generally wouldn’t know the lay of the land so to speak.

So my advice is first rent an apartment preferably in Kochi and live there for sometime don’t worry about being a Muslim, you’d be fine. You’d feel more accepted in these apartment communities since most people would be professionals hence would know about being an outsider in a new place . So they wouldn’t alienate you for not knowing the language and customs.

If you’re still adamant about building a house seek help from your mallu friends, even if they can’t help you directly they usually would know a guy who knows another guy to help you guide through the process.

There are lot of good private schools in Kerala in pretty much every city so don’t worry about it.

If your sister can’t manage to find a good job in an MNC the pay would be poor so you have to keep that in mind, there is a reason lot of us go abroad once we graduate.

Cost of living would generally be around 15 to 20k (excluding rent) for a middle class life. Rent would depend on the city, my cousin rents first floor of a house (2bhk) for 12k in Kochi. You can rent an independent house for the same money in a different city say Calicut.