By Grammar check, Uncountable nouns

Hi again, 1. For No. 1, can you put a comma to make the phrase non-restrictive and use it that way, without deleting it? You could, but it's rather awkward and unnatural. It will be good for them, the Christian students. 2. For No. 2, what if the list contains a mixture of countable and...

Hi, allow me for two questions. 1. For No. 1, can you put a comma to make the phrase non-restrictive and use it that way, without deleting it? It will be good for them, the Christian students. 2. For No. 2, what if the list contains a mixture of countable and uncountable nouns like this? How...