Aside from catching some names like Kenan Sahrmal and Arzakon, because I never played the PC game nor read the old novels featuring Shandalar, Yisan, Jalira, Talrand, and Kurkesh are the only Shandalarian denizen names I know of personally. What are some other at least almost definite Shandalar people's names?

For the most part Shandalar appears to operate on generic fantasy name conventions. There's no real linguistic consistency.

Arzakon isn't a Shandalarian name, though, as Arzakon was a planeswalker not native to Shandalar. There's Azar, though, which sounds somewhat similar. Sarlena, paladin of the Northern Verge also comes to mind. The wiki gives the names of the five guildlords as Alsadim K'mer, Starcryst, Lichlord Skavius Slan, Kzzy'n, and Morgane, the Great Druid. Then there's this random bloke who gets killed by Liliana in one of the webcomics, but I can't give you his name because the **** comic is buried god knows where.

Edit: Basically what Helio said, and keep in mind that different names come from different centuries or even millenia as well as from different races and cultures.

Actually, what sentient (at all) races are confirmed or heavily implied are native to Shandalar? Only races whatsoever I know of are Humans, Demons, Angels, and Slivers. I THINK Aven too.

Aven, human, demon, vampire, angel, salamander, sphinx, elf, fairies, dragons, merfolk, gorgon, ogre/troll*, drake, leviathan, Wurm, treefolk, Griffin, hydra, and a huge spoonful of miscellaneous beasts like thragtusk and the ursoth.

Slivers are explicitly NOT native.

*the onakke were originally trolls, but for some bizarre reasons that we don't know were changed to ogres.

Oh, sweet, thank you for that. No goblins? That's surprising. I don't know why but Riku gives me the vibe there'd be some oddities like Shapeshifters (that and vague examples of them in core sets) what's an Ursoth? Bear-like creatures? I very much would like to use Shandalar as a to/from setting for characters if not outright stories but unfortunately it is the plane I know the LEAST about, (besides the Onakke, Thune, Kalonia, etc) here's hoping since that tiny tease of a Conspiracy 2/_____ Fiora block, that maybe WotC will try to stay in the realm of the familiar since they're doing 2 strict "return" blocks back to back and Shandalar will be among the "new but explicitly familiar" blocks in the near future.

The ursoth (and it bothers me we never got a card for it) is what Garruk was hunting in his very first appearance.
I don't think we have any evidence of goblins on Shandalar, but the core set was less helpful there, never had any names attached to goblins.

What about shapeshifters and such? (A handful of core set/duel decks shapeshifters which usually gives the notion of Dominaria or Shandalar) and why aren't Slivers native to Shandalar? It is curious that today MaRo did a "" when asked if a humanoid Shandalar-style planeswalker was possible....

I'd say with the presence of the polymorphist magic, shapeshifters are less likely as a thing, but it's important to note that there is simply no confirmed evidence for such a thing. Everything else I listed had explicit confirmation by either features or ties to locations.

Slivers aren't native to Shandalar because they are an invasive species from another world. That was the entirety of their plot arc in the core set. The change in the look was indicative of their adaptation. And needless to say, it was a phenomenal bomb. People hated the new slivers.

Yeah, that makes sense. Huh? I didn't really get any fluff about slivers in M14/M15. I'm a member of the minority that has no qualms about these slivers. For starters we've seen no such slivers on other planes, and even still, thanks to Sliver Hive it's heavily implied those slivers are a strangely occurring evolution of the common-design of slivers. Even then, i dont really bother much with goblins being different between plane X and plane Y, or merfolk, or something like that.

The thing is, this isn't a situation where they are a commonly existing creature across multiple planes. They are ALWAYS exceptional. What's more, as stated, these aren't even from Shandalar, they aren't a naturally occurring species on the plane. It's at least minutely suggested they share a common ancestor with the Rathian slivers since they aren't from the plane.

Question remains: If they're not from Shandalar, how did they get there? What even suggests that?

1) they were only recently encountered in a well explored and populated region. They clearly just showed up.
2) there was talk of an enormous fossilized sliver at the heart of the hive and some sort of primitive history relating how it landed there, but it was all rather vague.
3) Shandalar is a rogue plane, it's not metaphysically stationary, so it seems likely to be related to that.

In all honestly, it's entirely possible that Rath clipped Shandalar at some point while it was growing to overlay with Dominaria. Rath had a habit of clipping various planes and stealing swaths of land and people. if I remember correctly, that's how Skyshroud happened and how the Kor ended up on Rath. So it would make sense if a chunk of Rath passed through Shandalar at some point and deposited some Slivers. Those slivers then laid low or were dormant until some event brought them to the surface.

Speaking of which, is there any confirmation Rath Kor came originally from Zendikar? This seems to be a common statement, even in the mtgsalvation wiki.

I'm pretty sure it was confirmed at some point by either MaRo (so not as reliable) or Doug (so, far more reliable?). I feel like it was a tumblr post, but searching tumblr is a pain.

It was something along the lines of "Yes, Zenikar is the Kor home plane. Now you all can finally see where the Rath Kor came from..."

Doesn't that mean the reverse could have happened? Shandalar's slivers got stuck on Rath?

No, they've been very clear that we have never seen the home plane of the Slivers yet.

Oh? Truly? Well considering slivers are known for adaptation, and if I'm not mistaken, aside from Zendikar (and Ir if I'm not mistaken) Shandalar has some of the richest/abundant mana in the multiverse, so it could very well explain the slivers' advancements on Shandalar (and even learning to utilise mana/magic, according to Ramaz and the sliver enemy--forget its name-- at the end of the Shandalar campaign segment of D14)