Who is Stink and Smelt from The Mostly True Adventures of Homer P. Figg and what is their importance?

Stink and Smelt are a pair of criminals who are in the middle of a scheme to find escaped slaves and sell them back into slavery. These criminals come across Homer on his first night away from his uncle's house and force him to help in their scheme. In the end, however, these men are not able to conceal their intentions from the man hiding the slaves and are found out. The men are beaten by the man they threatened to kill and sell into slavery despite his birthright of freedom.