What are four decisions that Friar Laurence makes in Romeo and Juliet?

Four decisions that the Friar makes in Romeo and Juliet have disastrous impact on the outcome of the play.

First, by agreeing to marry Romeo and Juliet in secret, he is essentially defying the wills of two families in order to heal the rift between them.

Second, after Romeo is banished by the Prince, he sends Romeo to Juliet's to say goodbye before his banishment. 

Third, he agrees to give Juliet a poison that would make her appear as if she is dead, so that she can be taken to the tomb and then reunited with Romeo in Mantua. 

And fourth, he decides to send a note telling Romeo of his plan to reunite them, but unfortunately the note never gets delivered due to a quarantined village.