Do the Droyne even know that their ancestors were the Ancients ??
Excellent question. What follows is conjecture on my part based on rather a lot of research into everything that has seen print about the Droyne.
First - Grandfather wasn't really a Droyne IMHO, he was what we now call Chirpers. The Droyne are a result of biological and psionic enhancement. It may even have been one of Grandfather's descendants that augmented the Chirpers into the Droyne.
Next, without the coyn ritual Chirpers remain Chirpers, do the Droyne remember the origins of their rituals? Did Grandfather establish the ritual to provide a route to augmentation as an alternative to his progeny's work...
Finally, do the Droyne rituals allow access to a greater repository of knowledge hidden in 'psionic space'?
The Droyne casting ceremony appears to psionically trigger genetic and psionic potential hidden within the Chirpers. Now since I am of the opinion that psionics is not magic but is instead some high TL mechanism to access and manipulate the quantum foam introduced in T5/AotI this leads me to the conclusion that Grandfather, and possibly the Chirpers and other naturally psionic entities (animal, plant, intelligent, dumb) either naturally developed these psionic abilities or psionics are actually a very advanced technology that was seeded into out galaxy by races that predate Grandfather and the Ancients by rather a long period of time.
One of Grandfather's main aims has been to understand how he came to be and what other powers exist within our galaxy.
To answer the question - no, most Droyne are unaware of their nature as descendants of the Ancients. But in time of extremis they can perform rituals that reveal the secret truths and allow them limited access to Ancient era technology.
A totally pastoral Droyne community faced with an extreme threat could suddenly equip its warriors with BattleDress and state of the art weapon systems 'conjured' from 'makers' hidden within 'psionic space' for example.