No the historical source doesn't "mistake" anything. It states that the Parthian arrows penetrated the scutum and proceeded all the way through pinning the feet of Roman Legionnaires to the earth. And in TES there are contradicting sources concerning all sorts of things. In that aspect TES is more realistic than other fantasy games.
Any sources contradicting
Heart of Annequine?
Okay well show what that glue is.
Glue. Humidity-resistant glue. The kind that would be made by bosmer to work in a high-humidity environment because that's the only environment they know.
Bosmer wouldn't grow wood around metal cores. For one they don't use wood unless imported (which actually I think refers only to a sect of Bosmer and not ALL of them. Probably the northern populations.) and how would you grow wood around a metal? Do you realize that those metal crossbows use rope, not string? And you need to use a crank to draw those metal crossbows?
First two questions: Wood Elf racial magic - the same way they make their shelters in Valenwood. They don't harm the tree to do it. And for those metal crossbows - Well, it certainly increases Draw Strength, doesn't it?

Actual strength needed is disputable, but possession of "superhuman" strength (As we know it) isn't out of the question for the inhabitants of Tamriel. To make the metal more flexible, it needs to be longer and thinner.
You're just being silly here. And that story is most likely mythical. In any case it has nothing to do with cartoonish over sized war hammers.
Yes, yes I am. That's why I italicized
Techniques. Redguards have a Technique for EVERYTHING!