I've only tried a couple more things, and I'm not past page 8.
I've tried to assign notes to keys on the keyboard in various ways and then use that to translate the first letter in each word and also whole words in the last sentence.
I've tried
qaz = C
wsx = D
edc = E
rfv = F
tgb = G
yhn = A
ujm = B
ik, = C
ol. = D
and
q = C, w = D ...
a = F, s = G ...
z = A, x = B ...
and
z = C, X = D ...
a = C, S = D ...
q = E, w = F ...
According to my interpretation of the hints we should not use dvorak for this, but we should make a connection to musical keyboards or just assign notes to keys. My biggest problem is to figure out what the input is to whatever "function" we're supposed to use here. It just says that there's a riddle in the last sentence, but the last sentence is huge and I don't think the answer is that long.
Now I've also tried the words 'fiddle' and 'fiddleriddle' as input to these functions, and I've also tried to use fiddle notes that go like EFGABCDEF on the staff of the fiddle and just ABCDEFG in the same pattern as the first one for the keyboard.