Holly's scenarios look valid. And like AUS Fan said, I cannot see any scenario that would promote the OUA winner higher than 3rd seed, with the runner up getting the automatic 4th seed. Similarly, I cannot see any scenario where the OUA runner-up can be seeded higher than 7th.
Could UPEI be still seeded 7th? Only if the host committee needed to do so in order for the Panthers to open play Friday night, as they are planning now. But if you look at Holly's scenarios they all would have UPEI starting on Day 2, which would suit the host team fine.