The Courtesan's mother
The irony of a mother submitting her daughter to prostitution is obvious. For one, mothers are the symbol of life giving, and this mother is taking life away from her daughter. Then there is the unlikely greed of a mother who cares more about money than she does her own flesh and blood.
The hospitality of Sir Bounteous
Even though he is unknowingly entertaining his nephew who has come to steal from him, Sir Bounteous treats his guests like royalty, and in a stroke of ironic genius, he offers to repay the thieves for the trouble of their own thievery, still so unaware of the conspiracy because he is trustworthy by nature and doesn't stop to question the motives of his guests.
Follywit's inheritance
Follywit is a thief who steals from his own inheritance. Literally, that's the case. When he steals precious heirlooms from the house, he is literally stealing from what he would inherit when his uncle dies. In another irony, he believes his endless conspiracies will never catch up with him, making his wit folly.
The succubus
The succubus comes in the form of Brothel's lover, which is ironic by way of disguise. Also it's ironic that making love to a woman opened up the man's soul to an evil entity. The connection between sexuality and dark spirituality is uncanny.
Mr. Hairbrain's loyalty issues
Mr. Hairbrain ends up driving his own wife away by being paranoid about her loyalty. This ironic cuckoldry is made all the more ironic by the fact that when Mr. Hairbrain hears Brothel explaining to Mrs. Hairbrain why their affair cannot continue, he mistakenly believes Brothel is warning his wife out of concern. He's doing it out of guilt. They've already committed the act. But nevertheless, Mr. Hairbrain invites Brothel to a party and grandstands as the host of his own sancho.
