Just becuase it did not exist in 2E doesn't mean I would automatically exclude it. A criteria to exclude a race on Darksu would be if it contradicted the major themes of Darksun, those being.
Survival
Environment
Slavery
Brutality
Magic Ruins the world
Everything is psionic.
Lack of metal
Those are probably the main ones .
Races I would exclude from Athas as player options (some might be there as NPCs or to be discovered eg Dray)
Any of the extinct ones (Gnomes, Orcs , Kobolds etc). Fine; that's an original setting conceit
Dragonborn (Athas does not have the traditional D&D Dragons, Dragonas are very rare, Dragonmen should not be there) Leaving aside dray and interpretations
Anything living construct (as PC option). Warforged for example don't need to sleep, breathe, eat, drink (ignores environmental/survival aspect of the setting) Less a big deal at higher levels
Extraplanar creatures (Tiefling, Aasimar) Athas is cut off from traditional D&D cosmology. Elemental creatures could be an exception. Demons are there, and a whole adventure is about an extraplanar invasion. Also, you're ignoring reskinning and stuff like the background of the Gith.
Anything metalic or heavily water based. Agree there
Anything with spell like abilities as a PC race. Change them to psionically-based
Most anthromorphic furries (Minotaurs, Tabaxi etc). Darksun lacks a lot of mammal based life forms. Depends; again, reskinning ain't a problem.
Plant races Change to cactus when appropriate
Classes
Arcane classes that are not wizards maybe Sorcerers depending on edition (3E sorcerer while boring had no bloodlines). They rewrote the 2E bard for a reason magic is hard. I think you're focusing too much on 2e-isms
Any class that gets around the themes of Darksun- Monks for example (unarmed combat is to good on a depleted world). On the contrary, that's why monks make sense.
Time travel based classes (chronomancers) Okay