Just to clarify things a little, maybe someone has a similar process but not for "licensing" purposes. The current process was created before I joined and the external partners were given Work licenses by the group, not realizing the cost being incurred.
We have external partners that come to us with product "proposals". They submit a request with documentation to get approval to move forward. The documentation is Approved, Approved with changes, or Rejected. If Approved the request becomes a Project and a series of further document approvals begins. There are different types of documents that need to be approved, these are split out by task. and tasks are assigned to "stages" in a custom form so the external partner can see what stage the project is in (stage will let them know if they need to act or if we are making a decision).
Some sticking points are: The internal group previously had the external partners inputting data into a custom form in the Project details, without a Work license this is no longer possible. It is data about the overall product that becomes available as the process moves along.
One external partner informed the group that they work with another partner in their Workfront and they have the ability to change the Project status themselves. I'm not sure how they have that ability without a Work license.
So, the internal group wants to have their external partners upload documents to a project, input data to the project (usually just a handful of fields) and ideally change a status to indicate they have done their next part. But we don't want to assign a paid license to these external partners.