ASP.NET / Office 365 SharePoint / RESTful API Wizard needed for integration

We have a scheduler software that was developed for us that allows us to manage and schedule equipment and employees. We need to integrate it with SharePoint in Office 365 using MS work flows and Ninetex workflows/forms. I imagine this needs to work through RESTful API's and possibly ASP.NET.

I need a user to be able use a digital Nintex form that will be used to create a new employee account, ideally in AD, as well as create a new list item in a list in SharePoint and then create a user in the scheduling software. Reminders/notification will also be linked the the list item in SharePoint