Wordpress Project Manager Pro - Custom development

We want to build an online client/task manager within Wordpress. The plugin "WP Project Manager" looks like a good base for us, but you can come up with some ideas to. The idea is: all our client get an own "project", so per client a project is made. within this project/business, all staff members are added en they can separately get permissions. So we can manage all our clients (+ staff members) from our online system. The client and their staff also need to get acces to the portal, only to their own business portal of course. We would like to get the following things done: - When we add a new client to the system we need to get a field with checkboxes. Each checkbox represents a "service plan", which the customer bought from us. The service plan exists of some PDF files en the most important: online forms. So when we check Plan 1 and Plan 3 while adding Business A, this business needs to get the PDF's and Forms from plan 1 & 3 after the creation. - Those forms need to be online and they need to be able to save it. So they can continue filling it out later and then after, send it to us. Ninja forms offers some good add-ons to create this. - Each client/manager/staff member need to get separate tasks and deadline, but this is already in the system. - We would like to add some custom email alerts. So when the client gets registrated in the system, they get an email. And when a deadline is near etc. I would like a freelancer, who can come up with ideas/tips too. If the WP Project Manager Pro plugin is not suitable for this project, also come up with an alternative. I look forward hearing from you! Please let us know the estimated costs of this custom development, so the checkboxes with forms and the email alerts. If you can do this successful, more projects are coming your way from us.