Airbus does employ in-house pilots on corporate shuttles.
On top of WDL and Privatair, they operate 4/5 corvettes (based in TLS) that are planned to be phased out in the next 2/3 years. All these crews will then be dispatched to other entities.
As far as I know, no chance to get a seat in a Beluga unless you're French, have 5000+ Hrs under your belt, and have a tick if some other mentioned boxes hereabove...
I think it's easier to get a job at the delivery center than in Airbus Transport Intl'...
5 Rings