I really don't know that many examples but there is always the example of Mother Teresa, a woman practicing a different religion, someone who developed their human qualities to much greater levels than most people on the planet. Buddhism might look at her Wisdom Parami, as not being as strong as we would like, because we have a different understanding that does not rely on belief. But how good was her Generosity, how good was her Morality, how good was her Renunciation, her Energy, her Patience and everything else. Her Parami development is these areas was very good. And there are bound to be some more people like Mother Teresa. I would like to hope there are some Jewish people equally as nice and kind. I would like to hope there are some Muslim people equally nice and kind, I don't know any Muslims personally but I would hope so. I hope the same for any other religion on the planet. Most religions do try to point towards doing goodness in some way, so hopefully that is the case.
To have a wish, the Compassion/Lovingkindness wish, that is easy. We can do the Compassion/Lovingkindness wish for everybody. To have Sympathetic Joy with people is only really possible if we know someone who has portrayed something that is very beneficial, a good quality or a skill that helps human beings. Sympathetic joy is very much a restricted meditation compared to Compassion/Lovingkindness.
It is possible to have Compassion/Lovingkindness for everybody, every insect, every animal, every creature; all beings on the planet and in the universe. However, you cannot have Sympathetic Joy for all beings on the planet and in the universe. Sympathetic Joy is different. Sympathetic Joy requires that you know something that the person did well, some quality that is admirable, something inspiring about them, something that they have done which helps other living beings. This question didn't actually talk about Sympathetic Joy difference of Compassion/Lovingkindness, but maybe that is what they meant. And if they want to talk more about it in the interview, feel free. So it is possible to have Sympathetic Joy with people from other major religions if you know something about them which has benefited others in some way.