I made my character and then just sort of looked at his face to get the first name. With the Van Dyke facial hair, Oliver just seemed to fit—plus I've always loved that name.
Beelzie is a homage to Beelzebub, my favorite persona in Shin Megami Tensi: Persona 3 and 4. When fusing personae, the resulting persona has the chance of getting any random skills from the previous personae, and I literally spent 3 days of play just in the Velvet Room fusing the damn thing to have the exact skills I wanted. I went with a cuter version of the name, Beelzie, since I'm a diminutive Lalafell and, thus, Beelzebub seemed too mighty and powerful for my FFXIV character.