Just trying to keep the narrative simple, yes there’s Akkadians in Mesopotamia before then but they’re not really in southern Mesopotamia where Sumerian was spoken. I said ~2300 BCE because it depends on what chronology you use, 2334 - 2279 BCE is the middle chronology dates given for Sargons reign but that can vary my +- a century so I tend to give rough centuries for events. You’re right that saying they migrated from the levant is probably a misnomer and I was just basing that on Akkadian being a semetic language, I’m not as deep into the anthropological or linguistic side of scholarship so migration theories aren’t my strong suit. And I should clarify that I’m saying Akkadian presence because it’s only after the rise of the Akkadian empire that semetic speaking people become a strong presence in southern Mesopotamia, whether that’s a migration of them or locals adopting their cultural practices is still up for debate among scholars.

Amorites are arguably first attested in the Ebla archive from the ED period though that’s northern Mesopotamia, and in southern Mesopotamia Naram-Sin claims to have fought Amorites on one of his campaigns. It isn’t until the Ur III period in the 22nd and 21st century, after the 2300 date I gave, that we have evidence of Amorites integrating into Southern Mesopotamia, and of course the famous wall to repel the Amorites

That’s a really cool idea but the connection would be really tenuous. Gudea was a single Sumerian king who ruled in Mesopotamia in the 22nd or 21st century and while Mesopotamia did have contact with the Levant for a long time, the name Judah which is the root of Judea is first attested in the Iron Age after the Bronze Age collapse, around the 7th or 8th century BCE. So different cultures and a long time span separating them

You’re right, sorry I didn’t mean to imply that IRVC = Indo European but I see that’s how it comes across in my comment

We really can't say since there's no way to know how the original speakers pronounced things. We can somewhat confidently restore what Akkadian sounded like due to comparative semetic studies and their syllabic spelling in writing. However, Sumerian is a language isolate with no known related languages for comparison, their spelling was mostly logographic (think chinese, a single symbol representing an idea), and the only way we know the associated sounds is through Akkadian who didn't have the same sounds to be able to accurately represent how Sumerian was pronounced. For example it's believed that Sumerian had several o sounds that Akkadian is simply unable to render, and instead get represented as the same u sounds despite the variety that originally existed. You'll usually hear it pronounced with a soft g today but that has nothing to do with how it was originally pronounced

I mean the only reason we can translate it is because the Akkadians (who really started migrating into the region from the Levant ~2300 BCE) made these long lexical lists so that they could learn Sumerian too. We were able to decipher Akkadian and then Akkadian allowed us to decipher Sumerian, though there's still a lot of work to do/being done and our understanding of Sumerian is far from perfect.

There's definitely a lot of information on the gods including their myths, how they were worshiped, what purviews and symbols they were associated with, though not from the foundation deposits I'm talking about. Those are really basic and the one I'm referencing just reads "For Ningirsu, strong hero of Enlil, Gudea, lord of Lagas, has made the old things appear splendidly, he has built his temple-of-fifty-white-anzu-birds for him, he has returned it to its place for him." If you're interested in Ningirsu's association with the anzu bird, and his epithet hero of Enlil, and really his main myth, here's a half way decent translation https://www.gatewaystobabylon.com/myths/texts/retellings/theftdestiny.htm

Probably not since the Sumerian pantheon is from well before Indo-European migration which spread the those figures throughout Eurasia, though there are synchronisms later in Mesopotamia history and at least one inscription which directly invoked Agni. There’s also a very loose theory that Harappan/Indus River Valley Civilization and the Sumerians were related, though there is no real evidence to back this up as of yet. There’s currently an ancient dna project testing if the IRVC and Sumerians shared ancestry, and if that’s confirmed then there is a possibility of synchronisms

The actual translation from the inscriptions on foundation bricks and nails is “e-ninnu-an-im-mi^mushen -babbar-babbar-ra-ne” where e is temple, ninny is fifty, an-im-mi^mushen is the anzu bird (associated with storms and chaos), babbar is white, and ra-ne are grammatical elements meaning his. So the name of the temple literally translates to “his temple of fifty white anzu birds.” But that’s kind of a mouthful so most people just use enninu which is the temple-fifty portion or call it the white thunderbird temple which is the anzu-babbar part. Currently in grad school learning Sumerian and we got to hold and translate some of the foundation pegs with that inscription!