New Frame - Floating Islands world

So I am a GM for middle-schoolers who wanted a world that has floating islands/steam punkish, airships and dragons in Dagger Heart (possibly Castle in the Sky, Mortal Engines, Avatar themes). I started to spec out the frame. Using a vertical strata, with denser, mineral-rich hanging lower, and verdant ones higher. The skies are thick with mist currents, magnetic winds, and beast-haunted thermal rivers.
Upper Skies - lush, porous, home to eleven slider villages, floating farms, lotus temples. Airships powered by Etherium crystals.
Middle Skies - Mixed culture trade drift, most populous, stable, safe wind tunnels, sprawling cities, built on chained isles, trade routs, Elven & Dwarven airships, human dragon riders, elemental sails.
Lower Skies 'The Iron Roots' - heavy metal rich islands, magnetism, geo-engines, lava forged, golem foundries, deep-stone mines. Dwarves and gnomes homes. Sky-ship, crafters, powered by Magnetar Rings (repulsion/opposite to Iron Roots)
The shattered sea below - giant swirling vortex, storm churned, fringe scavenger cults & sky-wreckers, contains dead titans and fallen machines.
Magic: sky runes, inscriptions used to control wind direction, protection, summon thermals
aether binding - tether large objects through magnetism (learning in school)
gravity weaving - arcane manipulation of mass, inertia and altitude (they are learning this in school). Titan's Breath - rare magic flight, weightlessness, storm shaping.

I have a couple of ideas mapped out: (a) a tether chain anchoring part of a city is failing, (b) a storm wrecked island returns after centuries of missing. (c) Retrieve an ancient sky map. (d) A massive dragon egg hatches in the heart of a drift city. (e) Old-world shattered sea monster returns.

My question, ideas for other adventure hooks or campaigns? Or specific frame conditions to add flavor or mechanics. Thank you!

The players: human muscle, clank repairman druid, elf assassin, faun sorcerer.