Congrats on the locks.
If your possible hets prove to be 100% then you would have a 1/16 chance of a caramel glow.
So if you paired your male 100% het caramel/50% het ghost to your 66% het caramel/50% het ghost and produced a caramel glow or a ghost AND caramel you will have proven both animals 100% double hets.
If you get a ghost you would have proven them both 100% het ghost. Similarly, if you get a caramel they will be proven 100% het caramel.
This wouldn't mean however they were proven to be NOT het ghost or caramel just because one wasn't produced. There could be a few scenarios that only continued breeding could answer. For instance, your male could be 100% het caramel/100% het ghost but you wouldn't be able to prove it if your female turns out to be only 100% het caramel. But after a few clutches with no visuals then I would conclude they were probably not double hets.