re: superficial questions. They might be useful given the large number of potential candidates available with current mobility. Why not limit the candidates to those who eat or not gebrochts, daven same nusach, vote the same way, pine for the same team, and squeeze the proverbial toothpaste from the same side. After reducing the friction, parents can consider other more important factors after that or leave it to the youngeles themselves.
That said, here is some useful advice I heard:
– from a Rosh kollel: “I asked only one question – are the parents honest in business”. Of course, this might be too humble. It leaves unsaid that he expected the family to have a business and probably multitude of other things that a Rosh Kolllel may take for granted
– from a Lakewood Rebbetzin: she inquired with families where the hasan was paying attention and good with their children, and she went to his shul to see how seriously he is davening. (This was not for her children’s shidduch, but for her own).