[X] Bottom Rung: The latter of the compromise options. Gwyndlyn will be in line for the throne, but she will perpetually be the last in line. The only way she will be named Empress is if every other potential heir is dead or otherwise unavailable. The nobility aren't likely to protest this, as if every other heir is dead at the same time they'll likely have much bigger problems to worry about.
[X] Gardening: He shall apply his understanding of botany and plant biology to the palace gardens, tending to the decorative flowers as well as the herbs and vegetables bound for the Imperial kitchens.