I am researching ways to create an approval process that would be assigned to a queue of users and have a final approval based on a majority approval. I'm not sure if a custom object outside of approvals should be created to handle this, or if dynamic routing of an approval process could mimic a majority approval?
I don't see how majority rule would work using native approval engine.
You can have multiple queues or users assigned as approvers for a given step, but the only options are unanimous approval from all step approvers, or first to approve/reject.
Neither would work for majority.
If you used separate approval steps, any rejection would prevent the approval from moving forward, which would not work for capturing majority.
You might be able to rig up something mildly insane with process builder that would allow you to automatically resubmit for approval upon rejection, and tweak the approval node criteria to allow skipping the previous rejection step. I think it could be feasible but it sounds quite possibly "overly clever", so you could test it, but I likely would go custom.
Custom should let you capture all approvals in parallel while using majority rule as the criteria.