I always struggle with whether or not the friar should be pardoned. He did cause Romeo and Juliet’s death, almost directly. The prince seems to pardon him. In Act 5, Scene 3, the friar seems genuinely grieved and clearly feels guilty for his part.
if aught in this
Miscarried by my fault, let my old life
Be sacrific'd, some hour before his time,
Unto the rigour of severest law.(Act 5, Scene 3)
I have to look back to when he first agreed to marry them though, to make sure he should be pardoned. When Romeo asks him to marry them, at first he does not agree. He changes his mind though.
In one respect I'll thy assistant be;
For this alliance may so happy prove
To turn your households’ rancour to pure love. (Act 2, scene 3)
It seems that his heart was in the right place. I would pardon him.
The two people who seem to be in the most peril are Montague and Capulet. As the heads of their families, they are responsible for everything that members of their households do. However, I do note that their grief is real and they want to reconcile. They try to outdo each other in apology. Capulet is first.
O brother Montague, give me thy hand.
This is my daughter's jointure, for no more
Can I demand. (Act 5, Scene 3)
But I can give thee more;
For I will raise her statue in pure gold,
That whiles Verona by that name is known,
There shall no figure at such rate be set
As that of true and faithful Juliet. (Act 5, Scene 3)
Am I satisfied? No. I have to go back further, so see who started the dispute. In the prologue, we learn that this feud is not new.
Two households, both alike in dignity,
In fair Verona, where we lay our scene,
From ancient grudge break to new mutiny,
Where civil blood makes civil hands unclean. (Prologue)
So Montague and Capulet did not start the feud. In fact, it is described as “ancient.” I can hardly blame them for this. It seems like this has been going on since long before they were born. I would pardon both of them too.