Sky creatures

Since Lera exists, it is possible there could be creatures that float about in the sky as if it was an ocean. Of course this depends upon how much Lerite is on the planet. in this rambling I'll explore how these creatures would exist, and how they'll survive solely in the sky.
I imagine it would be quite similar to the ocean, with phytoplankton forming the bottom of the food chain. So let's start with them. They are a form of microscopic plant that floats near the surface of the sea, and grow in the sunlight, they are innumerable, and their blooms can be seen from space. Now what if a similar plant could fly in the sky, quite high up to gain the most energy from the sun. In this way it would be like the ground, where humans live, would be similar to the ocean floor, this has insane implications if such flying creatures exist.
So if these plants bloom perhaps once every other year when the sun is strongest, they might block out the sun at least bit, further cooling it. This might remove the need for "Wild Myotra" to explain the long winters.
We've got flying phytoplankton, but wouldn't that mean an abundance of other sky going creatures? Do I really want sky sharks and sky whales flying about, possibly attacking land creatures? Perhaps Vona is not rich enough in Lerite to support such large and complex sky creatures, or at least not many of them. Where would these phytoplankton even get their lerite anyway? Clouds? It could condense into clouds? maybe they start life on the ground, and are brought up into the clouds by evaporation, then can grow in the humid and possibly lerite rich environment. This would also give them the water they need to grow. So we have Water, Lerite/nutrients, and plenty of sunlight. Each year they would bloom, turning the sky green, and raining down seeds that will restart the cycle.

Complex creatures

We might have a large amount of sky-fish, that feast on the skyplankton, to gain their lerite and nutrients, these too might start life on the ground, perhaps in mountains? Or... if flying creatures exist why not floating islands? It's entirely possible as long as they have an energy source. Though it would have to be electrical in nature... Ok nevermind, unless I want floating volcanoes...
Sky-whales are definitely gonna be a thing. Probably a bit smaller than a humpback, that kind of weight needs a lot of support, not to mention the amount of energy it would spend just staying afloat. Maybe they'd resemble manta-rays, with wings to help make staying in the sky more efficiently.
And what about predators? Something that hunts the sky-whales? Sky jellyfish? That might mean they'll hunt ground creatures though. Maybe I'll just stick with skywhales.

Sky-plants

This might explain how floating islands exist. A rare plant that starts out on the ground, grows to gargantuan sizes, growing a giant root system through the ground, until once every decade it rises up, along with the ground/root structure, floating up into the sky. It would then drift about, spreading seeds, and soaking up the sun, safe from ground animals. A cluster of these could rise at the same time to form larger islands, with their own ecosystems.
Of course these would be prime locations for sky creatures to nest, or gather the precious lerite they need to fly. like a coral reef in the sky. They'd also be targeted by Lerite miners, who know they'd be very rich in the mineral. The plants would be harvested, and the island soil crushed up to get the most lerite possible.
This is good, it sets up the possibility of humans destroying their habitat. By mining floating islands they destroy habitats and steal precious minerals away from the wildlife that needs it. it also means a whole ecosystem in the sky.
And of course there would be hybrids that can live on ground and in the sky, such as the Kypos.