First of all, Merry Christmas!
As for Silent Night, I think it should be done and - prior to the Novus Ordo - it was not uncommon for people to sing it at the end of Mass. The author was a Catholic and it has always had a big place in Catholic musical devotion.
Why don’t you write a letter to the pastor and say that you’d like to hear Silent Night at Midnight Mass. It’s the best-known hymn in the world, btw.
Yes, I might talk to the priest with my (yet another great) idea of how to fine-tune our really lovely church. hahah. Sure he’ll be happy to hear from me, once again....