You are an unreasonable parent, and there is nothing you can say or do to convince me otherwise. You are asking a child in 2nd grade to mow the lawn? Wow. I really feel sorry for your daughter and know this, she may grow up to resent the daylights out of you and rebel as a teenager, watch and see.
You should be doing the laundry and so should your sister. My 2nd grade children could not reach inside the washing machine top loader or reach the control panels either. Your expectations are way too much for the age of your child.
You are making a slave out of her while she is way too young and regardless if she is your personal maid, it is not producing income from your job to buy her extra clothing. So, your reasoning is way off balance. Besides which, kids her age grow out of their shoes and clothing before it gets all ripped and worn out. Perhaps you need to stop buying crap at WalMart.
Instead, shop at thrift stores for shoes for her to wear while she is cleaning the house for you and your sister and her daughter. Reserve her better wardrobe and clothing for school while she plays Cinderella.