the circumstances that lead to Glory becoming a Dragonet of Destiny are a little different in my AU
The short of it: it was part of a conspiracy for Magnificent to steal the Rainforest Throne
When the NightWings were bargaining for eggs for their prophecy, they got all but 1 that they needed.
Clay, from Asha who deeply believed in the prophecy
Sunny, after catching Stonemover and Thorn attempting to run away together and using her to keep Stonemover in line
Starflight, who was readily handed over by his parents who wished to see their class standing raised
and Tsunami, through bargaining with the Sea Queen and King during a time of desperation for them
Problem. All attempts to trade, bargain, plead, or even kidnap a SkyWing egg for the prophecy proved fruitless. Scarlet refused to trade or bargain for it, having a vested interest to keep the war going. And there were no viable SkyWing eggs that they could bargain for in the Talons of Peace.
So the Brightest Night comes, and the four they have hatch. But they need a fifth. And in their desperation, a few members of the NightWing Court concoct the idea: hey, RainWings can change color can't they? What if we tried substituting with a RainWing egg?
While Morrowseer was very displeased by this, they didn't have much of a choice at that point so he greenlit a few NightWings to bargain for a RainWing egg.
When the NightWings came to the Rainforest Kingdom, Queen Grandeur was unavailable, having been ill and bedridden for at least a week or more at that point. In her stead was Acting Queen and Royal Advisor, Magnificent. And Magnificent was oddly keen to pawn off a newly hatched RainWing, Glory, to them. A minor noble's child, she had claimed. The NightWings thought it odd but chalked it up to good fortune for them and left without any further questions.
What they didn't know was that Glory was in fact Princess Glory, daughter to Grandeur's son Prince Honor. Up until Glory, Grandeur had no surviving daughters or nieces, and was heirless. Her health was failing her, and many believed she may die soon. To which Grandeur declared that if she died with no heir, the throne would go to Magnificent, who was the closest (albeit still distantly) related to the royal family.
Glory actually hatched earlier than she should have. She was not predicted to hatch on the Brightest Night, and such came out small and sickly. There was much fear and concern over the health of the newborn princess, so soon after her father saw her hatch, she was whisked away to the medical canopy.
It was around this time, while still sick and under extreme care, that Magnificent pawned her off to the NightWings. The morning after they came, she tearfully announced the supposed passing of the young princess to a distraught Prince Honor and Queen Grandeur. Grandeur's health, already not the best, noticeably worsened at this news.
By the time The Dragonets of Destiny became 7 years old, Grandeur has held on but is very much close to death. It seems to most that Magnificent will take the throne.