hi no prob n I love such questions so have at it!
Lillith and Darah are different entities, Darah and Seth created vamps together, Lilith was their first successful vamp who had witch like powers like Alexei, she is canonically a vamp but due to her powers like Alexei, some think of her as a witch. Basically misinformation by lack of knowledge like Kor’s misinterpreted ‘death’
Hades was Seth’s disciple who had powers similar to medusa in which he turned things to stone and to an extent can change the atoms of inanimated objects but he cannot transform/change live beings like Seth. Hades is long dead now, but before I imagine him having a stone henge/Scotland vibe domain with scattered statues around.
Seth, Darah, and Lillith are a trio in terms Seth and Darah both had the power to spread death but Seth is the only who can zombify and rebirth creatures, changing their genes into a new, Darah was the only witch that can control blood, I think The best way to think of Darah and Hades relationship with Seth is Seth thinks of them as their students/disciples. Just a trio of macabre obsessed weirdos like the adams family
For the airships, its mostly rumors. Vortec is still technically advanced in terms of non magical inventions, and were in progress of making flying ships (in a literal sense of a ship that can fly, like in treasure island if you have seen that movie) but that invention faltered and vamps still rely on Vilebloods for flight instead. Basically steam engines and such was made by Vortec, while Ignians inventions all relied on magic hence they can teleport n such but can’t replicate with machinery.
For pheonix leaf there were actual dragons, but if they still exist now, they don’t make themselves known. Dietrich still use that as a slogan because they were in fact used to warm dragon eggs back in the day.