Solutions for Act I Scene 1 - Crib Notes

Given the presentation of the letters on children's alphabet blocks, the suggestion is we're looking for a childish theme, and title Crib Notes furthers this notion by suggesting children's music of some kind (interpreting 'crib' as a baby's bed and 'notes' as the musical kind). The more obvious interpretation of the title as a succinct summary of an academic course or text also suggests we're looking at the concise version of some sort of list.

Given the large number of lines, it's expected then that with or without the above hints, one should be able to recognise some as the initiailisations of the first lines of nursery rhymes. For instance, the first line SAS_S is such a conversion of the rhyme Sing a Song of Sixpence, whose first line is itself "Sing a song of sixpence". Clearly then the missing letter should be O for 'of'.

The lines then are as follows, with the missing letters highlighted in bold:

Sing a song of sixpence
Little Bo Peep has lost her sheep
Diddle, diddle, dumpling, my son John
Hickory dickory dock, the mouse ran up the clock
Mary had a little lamb
Little Boy Blue, come blow your horn
Yankee Doodle went to town
Half a pound of tuppenny rice
Jack Sprat could eat no fat
Ladybird, ladybird, fly away home
Twinkle, twinkle, little star
London Bridge is falling down
Baa, baa, black sheep, have you any wool?
Rock-a-bye baby, on the tree-tops
Do you know the muffin man?
Jack and Jill went up the hill
Hey, diddle, diddle, the cat and the fiddle
Georgie Porgie, pudding and pie
Wee Willie Winkie runs through the town
Old King Cole was a merry old sole

The missing letters spell out Old MacDonald had a farm, the first line of another well-known nursery rhyme. The ellipsis at the end of the puzzle suggests we should finish off the first line, giving E-I-E-I-O as our final answer to a puzzle concerned with expressing nursery rhymes as nonsensical strings of letters.

The answer is: eieio