Preparing for the end of term performance

Question

It's the first full week of term at Farthingbottom School and Portia, Felix, Primula and Randolph have arrived in the music room for their lesson. Professor N. Igma is nowhere to be seen, but he has left a message on the blackboard for them:

This term we will be performing four pieces of music at the end of term concert. Please practise them. Two methods will be required.

On the desk at the front of class is a single musical score:

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The children get out their instruments and try to play the music, but it sounds terrible.

Question: Can you determine which four pieces of music the children should be practising?

Answer 1

Cracked it!

The two anagrams at the top of the score are the keys to this puzzle:

Novas Requiem Cuts = Count Semiquavers (thanks, Zandar!)
Steve Chivet De Norman = Never Mind The Octaves

The first clue gives us three of the song titles:

Ignore the rests — they are just there to pad out each bar to the required length. If you count the number of semiquavers in each note or cluster of tied notes, then convert them to letters of the alphabet (A=1, B=2, etc.), then, with a few minor corrections, you get the following titles:

• Hallelujah Chorus
* O Holy Night
* Away In A Manger

The fourth title is encoded in the notes themselves. There are 57 notes, all of which are A, B or C. When grouped into threes, these form a series of 19 base-3 numbers, where AAA=0, AAB=1, AAC=2, ABA=3 and so on:

ACC BBB CAB ACB ABB AAB BAC ABB AAA BAB BBA ACC ABA CBB ACC BBB CAB ABB BCC
022 111 201 021 011 001 102 011 000 101 110 022 010 211 022 111 201 011 122
8, 13, 19, 7, 4, 1, 11, 4, 0, 10, 12, 8, 3, 22, 8, 13, 19, 4, 17

Using these numbers as offsets into the alphabet (A=0, B=1, etc.), we get the last title:

In The Bleak Midwinter

Answer 2

Not an answer yet, but some thoughts along the way that might help someone else...

The only notes in there are A, B and C (albeit in different octaves). This makes it unlikely that they are simply tunes mashed together in some way (like taking every fourth note, starting from an offset of [0,1,2,3] to play a given tune). Not many tunes are confined to only 3 notes.

6/4 would be a fairly unusual time signature but the bars do all appear to add up to 6 crotchets (quarter notes for you 'Murricans). However the patterns of notes and rests are all over the place. I wonder if the note lengths have anything to do with the encoding?

Presumably the "read between the lines" comment, the "Novas Requiem Cuts (5-11)" and the "Steve Chivet de Norman (5437)" are significant in some way. The "Novas" reads like a cryptic crossword clue but that might just be that I spend too much time doing crosswords.

Given the hint in the comment that "Novas Requiem Cuts" is an anagram of "count semiquavers" I counted the semiquavers in the first line:
8A 1C 12C 1r 2r; 12B 4B-1B 1r 2r 4r; 12C 4r 8r; 14B-7B 1r 2r; 8A-3C 1B 8C 3B 1r; 8B 12r 4r; 12A-3A 1r 8r