While its unknown whether Ingrith or anyone else knows about Diavals true form, theres some Black Comedy about Diaval being understandably uncomfortable being served a bird dinner, with him and Maleficent sharing an awkward look with each other.
There's something darkly funny about how Ingrith opens her secret passage by twisting the head of a dressing dummy like she's snapping a neck.
During Ingrith and Aurora's confrontation in the secret lab, Ingrith seemingly steps out of the shadows...then notices the beam of light coming from the window and decides to go around it like avoiding a particularly disgusting puddle...all the while giving her Motive Rant.
After dying, turning into a phoenix, and rescuing Aurora from a fall from a tower, Maleficent turns to Diaval and says, "I missed you." Diaval asks if she hit her head.
A few minutes later, Phillip sees a goat wearing his mother's jewelry wandering about and whispers "is that...?" Diaval insists that "Maleficent can turn her back" only for the king to suggest that maybe they all prefer Ingrith stays that way.
During the lead-up to the wedding, Diaval cheerfully apologizes to the humans around him in case some of them were among those he maimed while in bear form.
Maleficent tells Phillip and Aurora "I'll be there for the christening" and gives a wink. As she flies off, Phillip gives Aurora an uncertain look. At least this time, we know there won't be any cursing to death or death-like sleep.
It ALSO implies that Aurora is ALREADY pregnant after ONE night of marriage... boy, Philips fertile!