My sympathies on both the pain you're in and the death of Prince. I hadn't heard yet that it had anything to do with medications. Last I heard, it was thought to be the flu.
Regarding benzos and buspirone - they are very different classes of drugs. My PM doc described benzos as powdered alcohol. They hit the same receptors in the brain and depress the central nervous system the same way that opioids do. Combining them can lead to a fatal suppression of the central nervous system - you stop breathing, which does reduce pain, but for the last time.
The thing is, you never know if that one time you do it is going to be the last time. So even though you might have never had a bad reaction, one day when your pain was really bad, you hadn't eaten well and and and. For that reason, doctors tell us to never combine benzos and opioids (or booze, for that matter).
Buspirone is a different type of medication for anxiety. I get what you're saying - you'd rather take a once in a while pill than be on Buspar long-term. How about if you look at it this way tho: taking the buspirone helps prevent the anxiety in the first place, meaning you might not ever escalate to the point of wishing you could take the benzos.
Wishing you well

Shaggy