singular / plural verb?

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. A small minority of students are interested in politics.
  2. A small minority of the population are Buddhist.
  3. A large/small percentage of the population/people are Christian.
    Please correct the above.
    Thanks.
2
  1. A small minority of students are interested in politics.
  2. A small minority of the population are Buddhists.
  3. A large/small percentage of the population/people are Christians.
3

You do not need to pluralise ‘Buddhist’ or ‘Christian’.
Using the singular form is fine to refer to the faith followed rather than the person doing the following.

4

If the poster thinks so, then the verb ‘is’ (singular) will do well. It would mean ‘Buddhist or Christian population is a small minority’.
(But then can we say ‘Buddhist or Christian people is a small percentage.’? I doubt.)

5

I think you’re missing the mark with your interpretation.
It would mean
A small minority of the population are (followers of the) Buddhist/Christian (faith).