Hi TFT,
The only legitimate conclusion is that they rendered Elohim as Theos in the LXX version of Genesis 1:26 because they were clearly using Theos as a replacement word, borrowed from Greek, for the intensive plural Elohim. That means they are using Theos as an intensive plural and the characteristics of the word therefore have to change in order for the understanding to come through in the translation. It is blatantly obvious, crying out for attention, and yet ignored by every commentator I can think of. What led me in this direction is an even more critical situation that reaches down to the very core of what any one of us here believes. Does our heavenly Father "know" evil? There really is only one place this can directly be derived from what is written. And this kind of "knowing" is the same intimate knowledge spoken of in Genesis 4:1 where it is written that Adam "knew" his wife Eve and she conceived. Does our heavenly Father "know" evil in this intimate way? This is intended for good so my own personal advice would be to not even answer if you are inclined to answer in the affirmative after reading what follows below. It would be better to contemplate, study, pray over such things, and come back to this at a later time as you feel led, (rather than to risk the possibility of blaspheming just so as to defend a doctrine or paradigm). So again I say, rhetorically, (and not expecting an answer especially if it might be in the affirmative), does our heavenly Father "know" evil? According to the Masoretic text they say He does but according to the Septuagint the Tetragrammaton was not originally in the pertinent text:
Genesis 3:22-23 LXX
22 και ειπεν ο θεος ιδου αδαμ γεγονεν ως εις εξ ημων του γινωσκειν καλον και πονηρον και νυν μηποτε εκτεινη την χειρα και λαβη του ξυλου της ζωης και φαγη και ζησεται εις τον αιωνα
23 και εξαπεστειλεν αυτον κυριος ο θεος εκ του παραδεισου της τρυφης εργαζεσθαι την γην εξ ης ελημφθη
Genesis 3:22-23 Septuagint (Brenton Translation)
22 And God said, Behold, Adam is become as one of us, to know good and evil, and now lest at any time he stretch forth his hand, and take of the tree of life and eat, and so he shall live forever -
23 So the Lord God sent him forth out of the garden of Delight to cultivate the ground out of which he was taken.
Genesis 3:22-23 Restored Name KJV (Hebrew Text)
3:22 And YHWH Elohim said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:
3:23 Therefore YHWH Elohim sent him forth from the garden of Eden, to till the ground from whence he was taken.
If from the Septuagint we restore ο θεος, (ho Theos), to Elohim, (which surely is what is meant), then the Septuagint is telling us that the Tetragrammaton was not in the Hebrew text of Genesis 3:22 which they used to render the Hebrew into Greek because Kurios is not in the Septuagint text. In addition, if this be true, it is possible and even more likely that the second portion of the verse becomes an interrogative, as if [the] Elohim were asking, "And now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever?" In other words [the] Elohim are shown as not fully knowing all that the Father knows but, unlike the Father, they apparently have known good and evil, and therefore there is a questioning among them. We therefore have a reading that is anywhere from one thousand to thirteen hundred years earlier than the current form of the Masoretic Hebrew text which did not contain the Name of the Father in Genesis 3:22 as the Masoretic now does. And what if indeed the second portion of verse twenty-two is an interrogative which the Father answers to the Elohim by sending the man forth from the garden of Eden? Perhaps this is why the statement which follows in the next verse commences with a word equivalent to "therefore" as this makes perfect sense:
Genesis 3:22-23
3:22 And [the] Elohim said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever?
3:23 Therefore YHWH Elohim sent him forth from the garden of Eden, to till the ground from whence he was taken.
This gives us great insight into what those who rendered the Septuagint were thinking, (some three hundred years before the advent of Messiah and therefore without bias). It also gives us insight into what may have occurred with the Masoretic Hebrew text, which was compiled some 1000 to 1300 years later, for there are quite a few places where the Tetragrammaton appears to have been inserted into the text which are not found in the Septuagint. Were the Masoretes a little too overzealous in an effort to maintain the strict monotheism which separated them from the Christian doctrines of that time, (700-1000AD)? If they were they went too far in Genesis 3:22 because I know from what is written elsewhere that my heavenly Father does not know evil. When I saw this I saw Genesis 1:26.
Two general things that come to mind immediately are the fact that Greek nouns are all innately anarthrous, with the article being added for a kind of emphasis that isn't readily understood by English thinkers/speakers (and the same for anarthrous nouns themselves).
Greek anarthrous nouns are specifically referring to qualitative characteristics and functional activity of those "things" as nouns. So it's quite appropriate that Greek qualitative plurality is utilized in the attempt to translate the Hebrew intensive plural.
A qualitative plurality is subtly, but substantially, distinct from a quantitative plurality. Ancient Hebrew minds were virtually NON-abstract; while more modern minds became more and more abstract, as evidenced in language and culture.
Biblical Judaism and Christian Monotheism are both centered around qualitative plurality because God as Spirit and His Logos are, indeed, exactly that in the only terms that could describe and/or define Him. (His own Logos Self-defines Him by/as/through the Son, by whom He hath spoken unto us in these last days.)
All the more amazing that we have any cohesive integrity to scripture preserved through such a span of time from various epistemological mindsets and cultures, and languages in translation.
Rather than comparative minutiae, a more over-arching approach from this perspective would be helpful. I learned much from Jeff Benner's work regarding pictographic "Paleo"-Hebrew, even if it isn't definitive (yet IS insightful).
Tov ("good") and ra'a ("evil"), in their most encompassing sense, are best understood as "function/ality" and "dys-/mal-/non-function/ality"; and what you're presenting is tied directly to Theodicy when addressing Ponerology (and, of course, Hamartiology and all else that cascades from these).
Since God is Creator and "Functionalizer", He knows no dysfunction in any intimate manner. He's eternally familiar with every contingent potentiality and plausible possibility FOR/OF dys-/mal-/non- relative to function, because He is omniscient (and because of His incommunicable attributes, including His Necessity {Non-Contingency}). But awareness OF and provision FOR something is not the same as "knowing" it in any intimate manner, because He is not dysfunctional and IS Functionality.
Dys-/mal-/non-function/ality is privation and/or negation as subtraction by addition. For instance, a completely functional intricately constructed mechanism can have something added that negates functionality; like a wrench being tossed into the middle of moving parts like gears and levers, etc.
That addition of a wrench brings negation or privation to the functionality of that mechanism. A larger wrench and/or multiple wrenches added would illustrate that such privation or negation of functionality has a qualitative span or range of dysfunction by degree that is not quantity.
This is ra'a (Hebrew), often translated as "evil" in the OT, but also translated as calamity and a number of other words; and is paralleled as poneros (Greek).
Understanding this is the foundation for Ponerology and Hamartiology, as well as presenting a Theodicy for why an all-powerful all-benevolent God exists with a creation in relationship to Him wherein there is the existence of evil. It's also inexorably tied to Theology Proper and Anthropology Proper and Soteriology (and virtually every other sub-ology within General Theology).
Qualitative/ness (including for plurality) and functionality/dysfunctionality are two core themes that are vital to knowing and "having" the absolute, singular, central, objective, and KNOWABLE truth of the one true and living God (who is Spirit) by His eternal Logos (who is the Son).