Do I need the membership plugin for marketplace?

I actually have a couple of questions:

Like many people here, I want to start an Etsy type store. I want to allow people to create their own stores and we take a % of the commission. I was wondering if I needed to have the membership plugin. The only people that register for the site are going to be vendors. People who shop do not have to register for the site and I will have an email subscription they can sign up for the receive the weekly email. Do I have to use the membership plugin to make this happen?

Also, how do I limit the registered users access to site. I want them to essentially have an 'author' role where they can just post products and their profile. I have created a few dummy pages and they have access to an admin dashboard. I went to Settings > General and there is no option to limit subscriber access. Thanks for your help.