Whichever is short for
whichever one of X (a thing, not a person), and the word
one or the phrase
one of the, even the entire phrase
one of the X is often omitted:
Adjective
Take
whichever one of the books you please.
Take
whichever of the books you please.
Take
whichever books you please.
Pronoun
Take
whichever you please.
Now to your examples:
Adjective
a.
Whichever one of you broke the window ...
b.
Whichever of you broke the window ...
c.
Whichever you broke the window.
<!pronoun>
d.
Whichever broke the window ...
e.
Whoever broke the window ...
Note on
c.,
you is a pronoun; it can't be modified by an adjective. The preposition
of is needed to accommodate the syntax:
whichever of you.
Note on
d., as a pronoun
whichever refers to things, and
whoever refers to people.
Does that help?