Well, what will the Elves have access to, since that will affect what the Edain have access to? Everything up to the development of gunpowder?
It's hard! Which is probably one reason why lots of writers short-cut.That's my inclination too. But then we really have to pay a lot of attention while growing these cultures side by side as "organically" as possible that we don't make a huge mess of what they already have achieved, because we won't have a historic context to guide us more or less.
They'd have germ theory of disease, along with accurate knowledge of physiology and blood circulation and the functions of all the organs, 0f cells, and advanced understanding of ecology. They surely have incredibly efficient and perfectly sustainable farming, and as Samwise commented their produce is delicious. (Yavanna also gave the blessed lembas-wheat to all the Eldar, and maybe to Avari as well.) The Sindar would have excellent medicine for injured Elves and for sick or injured livestock, which the Noldor would learn. Their naturally winning ways with animals and plants would make it easy for them to domesticate whatever they wanted. Some of them learn to talk to animals.Exactly, what kind of things will spring forth from "advanced biology" knowledge?
That's the way with a lot of technology, isn't it? What the Men want to learn, they will learn -- from Elves, Dwarves, even Orcs. Some things they will imitate if they can't find willing teachers. For example I think they do learn metalworking in the First Age, and skip right from stone to iron because the Elves and Dwarves already had iron.The question of literacy I think often depends on if it is encouraged.
I don't know if there are. Tolkien seemed to feel that humans are worse at everything than Dwarves and especially Elves, and that the only thing we're good at inventing are new ways to kill each other and destroy the land and wildlife. It feels rather dreary to see things that way, though. The Numenoreans invented mummification, but Tolkien seemed to consider that a bad thing, too. He did think smoking was a great invention, though (it shouldn't even be dangerous, if the pipeweed is from Numenor).Is there anything the Edain are especially good at themselves? Because it would be a bit lame if for millennia they only copied everyone elses stuff.
A linothorax is quite hard and rigid and usually not combined with either chain or scale armour...