Yes, I heard the First Noel, too, wondered if it meant anything, lovely in any case.
Sulek seems to quote other music in his works quite regularly. I'm sure there must be some significance, but have not read anywhere what it may be. Perhaps ttle can enlighten us?
The last two movements of the 6th Symphony appear to quote a distinctive figure from Prokofiev's Romeo and Juliet. The 7th Symphony quotes Bruckner. The 8th Symphony quotes Tchaikovsky's Romeo and Juliet. I'm sure other works have quote as well, that are perhaps less obvious.