I was wondering if it was possible to use pro forms to essentially create a form that a user needs to fill all the required information like name, phone, email, company, website url, etc and most importantly a way to select a membership plan and on submit to purchase that plan from SureCart and use the information to create a member post type on the backend as well to be used in a member directory page.
SureCart has an API that you can interact with: Introduction
In Pro Forms, you can then use the Custom Action and add custom code to create a SureCart purchase. 
There is no out of the box way though.