I like the terms "Hebrew Bible" and "Greek Bible" because they're closer to objective, but yes, these works were developed in different ways, in non-comparable ways (the Hebrew bible essentially collected from the religious literature of a people spanning at least 1200 years, the Greek bible bolted together and redacted between around the 50s C.E. to a couple hundred years thereafter.)
As to the question about "Satan," that's essentially a Christian question, since the Jewish notion of shaitan, or "the opponent," is more a devil's advocate than Da DEBIL of backwater American fame. "The opponent" has to come up with some messed-up stuff specifically because the God of the Hebrew bible looks much better taking a bet with some other being than just jacking with Job for fun, just for example. God can't very well tempt Eve and then kick Adam and Eve out of the garden. Another figure is needed.
Regardless of the progression of the character of Satan, the more central questions you (Icy) point to have much more to do with religion and what they will do for God's sake, than with Satan.
The Hebrew bible passages you point out seem to dwell largely on the Conquest period, then there was the united monarchy (David & the census.)
One thing both periods have in common is that they date from a period of empire building, probably finally reduced to writing in a period of exile in Babylon. Babylon is a mighty empire; Israel must be portrayed as having been a mighty empire. Babylon is at its zenith; Israel must have had a zenith. Babylon can point to its might of arms; Israel must also have enjoyed such might. Israel, in short, must have sprung forth upon the world like a lion, no pun intended (for those conversant with the symbols of ancient Judah.) But Israel also had its unique history and that was not to be trifled with; there must also have been a period of tribal confederacy; the Northern traditions from those conquered a century earlier by Assyria (the so-called "lost" tribes,) must be accepted; and above all God must be vindicated as great and mighty, and most decidedly not vanquished. We were sort of like Steelers fans before Rothlisburger, I suppose. What was still important was that back in the 70s the Steelers were great and mighty, and will be again. You get the idea.
Now then, the question arises whether the decidedly genocidic character of the Conquest as recounted in the Hebrew bible is historically accurate. There are difficulties getting to a lot of different sites (even worse for the united monarchy period, because that period revolves around Jerusalem... good luck digging up oh, I dunno, the Temple Mount. Politics is the enemy of archaeology there...)
However, we should find what the trowel and spade crowd call "destruction layers" where the Israelites came in first to Jordan and then to Canaan. We find many things at the sites thus far excavated: we find characteristic pottery styles, we find characteristic implements and weapons from various cultures... but we don't find the appropriately dated cataclysmic destruction layer, consistent with the many towns mentioned in the bible having been wiped out.
If you are a biblical literalist, you will notice that the prophets often talk about how the Israelites were too lazy about the genocides commanded (and claimed to be carried out) in books like Joshua. Apparently, even text within the bible says the utter destruction noted elsewhere did not happen, at least not to a "satisfactory" extent.
So the question becomes, do we or do we not believe that the spiritual value of the Conquest narrative is bound up with the commandment to genocide, or are we seeing something very ordinary for the period, i.e., a claim of great and terrible military might? I think the latter; I also think that to the extent it is instructive, it is as a remnant of a time when the more complete a genocide, the greater a society was.
Disturbingly, this period (which has always been an enormous source of dark meanderings for me,) seems not to bother many people. They take descriptions of SOME other cultures' putative failings, and explain how they were so evil they deserved it. We don't think like that anymore though. You can't say that every single Frenchman should be put to death because of a few mimes, and you wouldn't (now) say that every single member of a society should be put to death because of an aberrant practice foisted on them by their leadership. Least of all would we say it's acceptable to kill every man, woman, and child just to have them out of the way.
Fortunately for my conscience, it seems not to have happened. (whew.)
Another period you point to from the Hebrew bible is that of the United Monarchy, and that's a much more interesting example of competing viewpoints in the text. That's due in large part to the presence of the northern ten tribes' refugees among the Southern kingdom, after Assyria destroys Israel but Judah (for a century or so) survives to be conquered by Babylon.
This illustrates a point about the construction of the Jewish canon; to a larger extent than in the Christian counterexample, you can see a variety of viewpoints and traditions reflected in the text.
So for example you have the "doublets" and "triplets" in the Hebrew bible. One region has a story that Abraham passed off his wife as his sister before the Pharaoh in Egypt, and another story says he did it before a local king in Sinai. Both stories are reflected in the bible - probably it's the same story, with a different tradition handed down.
Some conflicts among traditions are less incidental. One tradition says Saul was announced to the people as the united monarch by Samuel, with great acceptance by (to coin a phrase) God and Everyone. Another tradition says Saul is a surprise pick, a bumbling incompetent scared of publicity, hiding among the peoples' baggage so as not to be noticed. One source extols the great things the monarchs do; another source considers the kings tyrants, and has Samuel lecture about the terrible evils of kingship, and the special evil (as you point out,) of taking a census. There is simultaneously a preservation of the monarchist and anti-monarchist viewpoints in the same corpus.
Again, bear in mind that the stories were rehashed and put together in exile in Babylon, from fragments and from oral recountings the exiles brought with them. The Bible at that time was the corpus of Hebrew literature. It was the things we had to remember to be a people; exile from the home itself made the Jewish people tie together all their stories and experiences and compile them in a way that all players could stomach... this is very simplistic, but it is a large part of the way this literature came into being.
In the context of this mode of compilation (actually this probably came way earlier than the Babylonian captivity), it may not have been very sexy to say "oh this town? Well a few of those Semites, close kin really, that were working in Egypt settled here, we liked their ideas, same goes all over this valley, badda bing badda boom, now we're called Israelites," or some (probably more complex) version of the same story. From the absence of destruction layers, my guess - and that's all it is, really - is that historically there was war where and when necessary, and there was intermingling where and when it was permitted. In retrospect, a conquest is a lot cooler story (until you get to the modern era, and we have to consider that killing defenseless women and children is no longer a virtue.)
Now then Icy, you've got a hell of a good (if oft-repeated) question there for the biblical literalists.
The question for a non-literalist who is a believer, at least from the Jewish point of view, is what we've learned from the extensive tapestry of our own history (whether you take the conquest literally or not, it makes a hell of a comparison and contrast with subsequent history.) This is not as neat an exercise as literal adherance, but it has really been the project of Judaism among even the orthodox (although their thoughts on archaeological findings are not often open-ended, the Talmud is remarkaby plastic in its discussion of many aspects of Torah, though more often than not consumed with every-day case-law type situations.)
Satan doesn't much enter into it from a Jewish perspective, but from a Christian perspective, it's certainly a funny question.
As to the assertion that everybody ate hallucinogens and that's why it's all so effed up looking, it's sort of lame. It's an example of looking around at what we declare illegal and pointing out that this stuff was all over the place. Well, it's true that Patmos is a great place to find psylocybin mushrooms, and coincidentally is where we get works like Revelation. It's also true there's qat in the middle east, but there's no record of use among the Israelites (not that it didn't happen, there's just no reason to believe it was a prerequisite to writing scripture.)
But if you want a mind-bender, don't look to drugs, whose effects are local and easily defined as unusual; look to the ambient legend of your town (or their town,) of your culture (or their culture,) of your nationalistic bravado (or theirs.) Look to the old game of "telephone," and think about a few centuries of "telephone" before it's all reduced to writing.
I guess my point is that to really look for relevance here, for those who do, it's not as easy as saying "boy I betcha they were all just stoned [pun intended]"
It's easy to not believe... it's easy to believe blindly... it's harder to accept evidence and also accept significance in a national epic, understanding it is not history or reportage. To shine a light on what is significant, you have to look to the methodology of reportage and history to see what point was really being made.
Just my two sheckels,
PFnV