How does Harper Lee use minor characters in To Kill A Mockingbird to explore some of the main concerns of the novel?Chose three of the following:...

I think you will get several answers to this question - so
I will tackle only a few of the options.  First, let's consider some of the smaller of
the main concerns of the novel (themes, if you will): hypocrisy and the difficulty of
being an "outsider" in a small southern town.

Grace
Merriweather - is used as a character who presents hypocrisy.  In her "missionary tea"
Scout records fairly accurately (if not unintentionally) the sheer hypocrisy of the
"ladies of high society" that gathered together that day in the name of Jesus.  The
point of the Missionary Society is to discuss (and presumably financially support)
missions work in other countries.  While the ladies lament and allow their hearts to be
broken for the lost souls scattered throughout the world - and back up the effort to
help them and eventually save them in the name of Jesus - they then turn and badmouth
the Robinsons and other black families right there in the town of Maycomb.  One says
something to the effect of, "There's nothing worse than a sulky darky."  How can the
same woman spread the gospel and then turn and degrade someone in her own town in
practically the same breath?

Dolphus Raymond - the short of
his story is that he chooses to live (and has had several "mixed children") with black
people.  He is white.  This is socially unacceptable in the small town of Maycomb.  So
he walks around with a brown paper bag - which everyone assumes he's drinking liquor
from.  It turns out he is not a drunk at all - he is merely drinking orange soda - but
it is easier for him to live with the reputation of being a heartbroken man who turned
into the town drunk - than the man who chooses to live with black people.  What does
that say about this society?

Miss Caroline - also
demonstrates the difficulty of being an outsider in a small southern town.  With all the
best and brightest intentions in the world, she starts the first day of school with a
fresh face and a fresh dress... she learns within a few hours just how much she couldn't
possibly learn in her school-teacher-training.  She knows nothing about any of the
families of the students who sit in her classroom - and what is worse - she is the ONLY
one in the room who is so ignorant.  The comical scene of the adult teacher learning
from one of the young students in the class only heightens the pity the reader feels for
Miss Caroline - because we are the only ones who know it really isn't her
fault.