What is the minimum percentile that a Non-Christian should have to get into XLRI for MBA through XAT?

XLRI doesn't have any kind of religion-based cut-off nor any reservation on caste-based. As XLRI is one of the most reputed colleges in India, the percentile required for non-christian is the same as for a Christian candidate.

Cut-off depends totally on the performance you have done in your exam. Above 90% is required to appear in GD and PI and after that, you get your seat. No institute has based cut-off based on religion, castes in the world.

In the Indian education system, no one can bias on the behalf of any caste, religion, sex, it all depends on your performance and your outcome will tell your future. Don't think about anything just focus on your studies make a strategy and implement it if you want to crack your exam.