I like your chances too.
Did want to say that your second to last point about not needing sponsorship is a moot point, as there is no sponsorship for a tourist visa. Further, having someone in the US willing to provide for you can act as a negative, as it can be seen as an incentive for you to stay as you have financial sponsorship. Having had a US visa in the past (pre-ESTA), the CO is looking for reasons as to why you will leave, versus reasons for why you might be tempted to stay.