You're right about the Main Character and Influence Character. Each one has a complete set of character elements. These elements describe the POSSIBLE places the problem might be in each of their throughlines, but only the PROBLEM element in each throughline is the cause of conflict in the throughline. So, while you may have your Main Character explore all of the elements while trying to solve his personal problems, only the MC Solution will do.
Both the MC and IC also have Overall Story counterparts (more accurately, the players that represent the MC and IC also represent players in the Overall Story throughline). Therefore, their roles in the OS (and the elements assigned to those characters) give them something to do within the context of the Overall Story. For example, Luke Skywalker--as MC--tries to work out his personal problems and learns to trust his instincts, while he plays protagonist in the Overall Story as a proponent in fighting the Empire.
The different patterns within each class are understandable when you look at how the Dramatica structural model is built. The bottom level is where the elements from which you build your Overall Story characters are found. Unlike the top three levels, however, each item does NOT have its own unique label (e.g. Pursuit and Consider). There is one set (or what we call a "chess set") of 64 unique labels which cover all of the elements for a single Domain/Throughline. Dramatica consists of four Domains and the elements appear within each of these Domains. The DIFFERENCE between the elements of one Domain and another is the arrangement of the elements within the quads. Though a dynamic pair is never split (e.g. Pursuit and Avoidance), it will be paired with different dynamic pairs to make up each quad. The combination of the four elements within each quad is different from domain to domain. These combinations create slightly different contextual "flavors" for the elements which substitute for unique labels. Therefore, Pursuit in a Situation domain is subtly different than Pursuit in an Activity domain because of the shared elements of the quad in which it is found.
Picking elements for MC or IC do not control which elements you assign to their functions in the Overall Story throughline. Build the characters however you'd like to.