Update SharePoint Hub Site to Integrate Sub-Sites Across Office 365 and Teams

We are in the process of reorganizing or establishing a more developed SharePoint integration into our workflows. We are a professional services firm that covers multiple lines of business, and affiliate entities (for example, we have a registered investment advisor, a law firm, a financial consultancy, and so forth). Consequently, we want to formalize our SharePoint Hub Site and properly integrate, streamline and fix broken aspects of the integration of current or future Sub-Sites. Presently, there is one Hub site, and three Sub-Sites. The Hub Site will maintain all documents and other assets, but must: - allow certain Sub-Sites access to only specific folders/folder trees of various libraries - have appropriate, and consistent permissions granted to all users without our current Groups and Users - Integrate the HubSite and SubSites into the Teams environment - Allow for the HubSite and SubSite "Groups" and Contacts and Calenders to be accessible via other Office 365 applications. - Similar tasks associated with harmonizing SharePoint, OneDrive for Business, Teams and Outlook. We have already completed considerable work in this regard, and at this point the job essentially adding a professional layer of expertise to what has been developed internally. Many of the above described tasks have been completed or attempted, but it is clear that they must be improved by someone with greater experience. We will either provide an hourly fee and then allocate those hours in "blocks" to ensure there is a good working relationship and appropriate skill level; however, we do believe that once the framework is established we would seek to migrate to a retainer-based model (monthly or weekly) to assist on an ongoing basis, project-based fee structure, or simply retain the hourly fee structure. We are flexible in this regard, and simply ask that those who submit bids be flexible for the first 5-10 hours of work. We work with very sensitive and confidential information, and so those who bid for the work will need to provide an NDA, and also allow us to get a sense (from the first 5-10 hours) of how compatible their skill set is with our objectives. Looking forward to finding a good fit! Thank you for considering this work and project.