Because Children were being put to work, not getting paid, he dangerous conditions. Children were getting hurt while working.
Plantation owners were heavily reliant of slaves, so yes it’s true
Michigan entered as a free state as it was one of the most north states of the U.S and still is. That meant it was filled of people that had a bad tone towards slavery. Florida is one of the most southern states and was filled with cotton farms in northern Florida ( South Florida was uninhabited by Americans cause there were marches and alligators I;e Everglades) Iowa was also a free state. Iowa was near Michigan and also had a population that disliked slavery.
Both were members of the Sons of Liberty