It has been a while, but progress does not rest in this effort. After all of the research-intensive work mentioned here (getting the HBA flashed to a newer firmware, making sure the drive cage was powered properly, etc.), I was finally able to implement the RDM/LUN solution mentioned by Lalegre. As such, their solution shall be marked as the accepted solution. But I will also link the relevant prerequisite information, in case anyone tries anything similar to this, so that they won't face hardware compatibility issues like I did.