Do APIs exist for a work item creation wizard?

As an exercise to become more familiar with Jazz, we tried to create process templates using our process authoring tool, but we ran into some limitations with respect to what was allowed to be specified for the default work items. My colleague, Sutthi, has already created separate posts for these issues, but we are now considering a different approach and would like to get your opinion.

Instead of creating the bulk of the items (tasks, work products, etc.) described in the process description upfront during project creation, we would like to build an instantiation wizard that would allow users to select entities from the process description and instantiate them as work items on-demand. We already have a metadata representation of the data from our tool and are wondering if the necessary APIs exist for us to be able to:

1. create a wizard UI for both RTC and web UI
2. create work items of various types
3. specify the values of work item custom fields during creation
4. create links between the newly created work items

I realize that these may seem like simple questions with obvious answers, but we were surprised to find out that some of the above were not supported in the process specification so we thought it best to ask here before investing further. Our understanding is that we can use the same APIs that are used by RTC so I am assuming that once the project is created, we should have full control over work item and work item link creation. Is that correct?

Thanks,
Dave