Is it hard for a baritone to sing F4? Many people say that baritones cannot sing Silent Night in C. Is F4 really too high for a baritone? Do you find this too high? This is what the organists have been telling me. Is this really true?
Depends on the baritone. Professional solo baritones frequently are called on to sing F4 or even a bit higher.
In choral parts, it's pretty rare to see F4 for baritone, though. In choral situations, the highest common notes for baritone are likely to be around D4 or Eb4, occasionally E4.
Really, it depends on the singer. Professional singers who call themselves "baritones" often find it much easier to hit high notes compared to amateurs who call themselves "baritones." A lot of introductory voice lessons for men often goes into proper technique to sing high notes without straining.
For operatic singers, typical highest notes in operas are:
Baritone: A4, or even G#4 for Helden baritones
So, for a (professional operatic) baritone, F4 would not be a very high note, and no problem to sing it for a trained singer, although it is not in the lower range either. Operatic baritones must be able to sing at least the A4 when vocalizing, and then it is easier for them to reach the lower notes too.
Back to your question, I would agree with those organists on the fact that it would sound better if the baritone sung Silent Night a little lower so the high note is lower than F4. The characteristic of that song is not very dramatic so a lower range would suit it better. You should try different keys of the song and hear and feel what fits your voice the best. Maybe drop the key a few steps lower so that the highest note is C4, C#4 or D4 instead of F4?