You should cross post this to r/LiminalSpace, they would love it.

Yea that all sounds nice but we can put ourselves in their shoes. It's not like some alien race that we have no knowledge of. These are people with very human qualities, and if it was obvious to them it should be obvious to us. This is a classic example of where you should apply Occam's razor.

It's probably not written down because there was no standard. Hoplites trained themselves if they even did that much. Underhand or overhand? Depends on what they were more comfortable with. What they did at the front line? Probably a bit of standoff fighting techniques combined with tactical repositioning, maybe with cavalry, something like what you see in the opening of the Bollywood film Panipat. Though obviously we have no proof and every battle was different but are you really about to run head first into a bunch of dudes with swords? Seems pretty obvious to me that no, not even in a battle would people be that stupid.

Homo Heidelbergensis, not homo sapiens. We evolved in Africa and migrated out to populate the world. To pick a random ancestor the human/chimpanzee last common ancestor (CHLCA) is theorized to possibly be graecopithecus, whose fossils were found in southern Europe. So at some point between CHLCA and homo sapiens our ancestors migrated into Africa and stayed there. The implication is that other human species could have left Africa sooner, or never came in the first place.

Honestly I don't think there's any reason to think they would be much different behaviorally, we know at least 3 species of human have mated in the past. They also existed well into the time period of modern humans so I would bet we mated with them too but it may not be easy to tell in the genomic record. They probably wouldn't mate unless they were similar in many ways, but mainly behaviorally. Classifications that distinguish between different species of human are mainly physical differences, this leads me to believe that ancient human species were much more alike than we would be led to believe by our current colloquial definitions of species.

You probably would if they evolved to the point of extensive tool use and creative abilities. And then gave them another half a million years.

And that can be traced back to survival instincts. Storing extra food and supplies for the coming winter.

You know, I don't even want any of this skin on my personal space.

I don't think they do sculptures off of the DNA when they make these renderings. I'm pretty sure I watched a doc one time and it explained that they actually re build the muscular features based off the skeleton and then add skin and other features on top. Not sure about that Chelsea exhibit but for the ones they did during the doc that's how it was done and it seems like a better method than trying to reconstruct based off of DNA alone.