Here is what it seems like to me...
The 3 dudes, to me, sounds like the Lord and 2 Angels...notice how Abraham says Lord? The name wasn't refused...remember another time when somebody bowed to an Angel and the Angel said not to do that? This person did not say stop...
And you see several references to Lord...
And when they go to leave, Abraham is conversing with one dude...calling him Lord while the other 2 went on their way...
Remember, Sodom and Gomorrah, it was 2 Angels that went there, told Lot and his family to get out...2 Angels...
So, it loox like 2 Angels + the Lord = 3 Dudes coming to Abraham and Sarah...my 2 cents...
This is a fascinating topic, imo.
When I did a word-by-word with the Hebrew Interlinear, I see several terms pop up in regards to the three men: Anshim (mortals) seems to be the one used in Gen 18. And of course Yahweh.
What's interesting to me is that these three (or perhaps Yahweh alone) claims they will return to Sarah and she will be pregnant. As though they needed to return in order for this to take place.
When we fast forward to Gen 21, where we see Sarah conceiving and the Lord returning at the appointed time, we see the name Yahweh mentioned again ... but now we also see the term Elohim mentioned, specifically in regards to what was spoken previously to them about the set time. It's my understanding that Elohim can also refer to "angels" or groups of "angels".
So it seems a bit ambiguous to me ... were the men with Yahweh mortals, or "Elohim" ? And is Elohim referring to Yahweh, the collective three of them, or angels specifically ?
The reason I find this fascinating and perhaps crucial, is because of all the "pregnancies" which seem to be crucial turning points in history.
Jesus is birthed by Mary, via the Holy Spirit and a female (obviously lol). It's announced by angels, etc and so forth.
Isaac is birthed by Sarah and arguably Abraham, however there is some intervention on behalf of Yahweh/Elohim ... whatever that means. And it is announced via those three.
So with Jesus and Mary, we have NO human male involved in the pregnancy of Mary. Just the Holy Spirit, and Mary. Angels announce it. However with Abraham and Sarah, Abraham is involved (a human male), it's announced by Yahweh/three mortals/Elohim ... and their involvement is somewhat confusing.
I'm not trying to open up a debate about Gen 6 ... only throwing this out there for contrast. In Gen 6, it's often debated if these Sons of God are spiritual beings/angels/etc which actually reproduce with human women. Considering that idea, the result was undesirable (the Nephilim). So, from that POV, you have an unsanctioned meddling with human females on behalf of these "Sons of God". We then have the earth filled with violence, the flood to wipe it all out, etc.
So when I look at it, I see a pattern:
* Unsanctioned meddling with humans (births) possibly in Gen 6 (the fallen ones). All wiped out. Possible spiritual beings mixing with humans.
* Sanctioned births with humans ... yielding Israel (he who struggles with God). Yahweh involved, possibly Elohim/angels.
* Divine birth, yielding Jesus the Christ. No males involved, no angels involved apart from announcing, Holy Spirit and human female only. Redemption of man.
I mean, I see a pattern in regards to crucial, debated, turning points in human history involving God, angels, and the birth of nations, and the symbolic nature of their names, their fate, etc. Again, I'm not trying to start a debate concerning conspiracy theories (I know what some of them are lol) or even if Gen 6 is actually describing "angels" and women making offspring. Just showing a pattern, and why perhaps identifying those other individuals in Gen 18 may yield a lot of insight. Personally, I have my own idea who one of them might be, but I'd be somewhat guessing ...