@Lawrence280
Other platforms do not take a higher percentage. They charge the guest 14.2%+tax and the host 3%+tax. If you list on multiple platforms then you can, via your account settings, move to simplified pricing where the guest pays nothing and the host pays 15%+tax.
To be a host just create a listing - Its that simple. To be a superhost if you have the right number of stays AND 5 star review you should get it within 3-6 months.
Business/personal - no idea - what country are you in?
You are not allowed multiple accounts so the final answer is easy.