Yeah, I’m aware the current Zandalari prelates live off of their faith in Rezan and his return.
I personally think getting entirely new prelates this way is a bit hmmm (he’s not even the Loa of Kings anymore, that’s Bwonsamdi now), but for Zandalari prelates - sure. Trolls in general? …no.
After reading all of this. The only ones who are hard to pin down. are Gnomes/ Goblin and Void elves and Undead.
Every other Race can look at their Priestly connections.
The Lok’osh angle for Orcs is splendid.
Trolls following a different Loa who’s teachings are in line with the Light’s teachings makes sense.
Night elves/Borne going the Elune route. No brainer.
Worgen just being Silver hand, because Their kingdom falls under the Church of the Holy light. makes sense.
Kul tiran Inquisitors becoming a Holy-er order? solid angle.
I did not know Chi-Ji’s teachings were aligned with those of the light. but yeah. that’s how it should go.
Dracthyr if they ever get new classes. would go with the Tyr angle as he’s their Indirect Creator.
But for those i mentioned at the start. Yeah those will always be tricky. Both Gnomes and Goblin, simply because they are pretty Faithless to begin with. Basing their lives on Science and logic. and Faith doesn’t abide to logic. finding an order for them that would Have Conviction and be Pious in the name of The light/Light adjacent deity will be a Stretch. not impossible, just takes extra lore to be added.
Forsaken and Void elves have the problem of being Light averse. Both being able to be Priests because Shadow priest exist. But we also got Alonus Faol who just powers through the pain who hold onto his faith. so its not impossible, but again also needing of a little bit Extra lore to be set up for it to work.
All in all. a solid list of concepts.
Forsaken can use light magic and can even be healed with light magic, it’s just painful as all hell to both receive and use. There are holy priests forsaken since Vanilla, with some of the most common NPCs that come to mind being the Argent Healers that cure you of the Plague debuff in both 1.12 and WotLK’s prepatch.
It just takes a very devout individual to do holy magic as an undead, because it is described as being excruciatingly painful; and undead are quite resilient, so, most will probably avoid being healed with Light magic if they can help it, given how a minor wound is far more acceptable than feeling like someone is burning you alive.
Ontop of that. Paladin are infused and empowered by the light. we got well documented lore for that on The Silver hand paladin. and we know that the Blood knights Empower themselves via the Sun well. Sadly we have not been given any empower/infusion details for Sunwalkers and Prelates as of yet. but it is safe to assume its Baseline for All Paladin to be paladin. So that would mean that there has to be Light inside the Forsaken at all times. which makes it a lot more painful for them to become paladin.
I know of the Zeliek angle. and he could have been classified as a Plate wearing priest/death knight more than a Paladin/deathknight. seeing as he just kept hold of his faith much like Alonus Foal has.
I think that most people are seeing it in the angle that Alonsus Faol is the person who created paladins in the first place in life, and he’s currently been placed in Lordaeron since 9.2.
Either they could go for a Darkest Dungeon’s Leper Knight-like / Knight-Penitent angle, or they might find a way on how to do it without it being extremely painful (through one way or another), given how pretty much the reason why paladins exist as a whole is right there, waiting to be written into some plot in quite literally their backyard.
I wouldn’t mind a mix of both, but I’m hoping for a lean on the former, if it ever does end up happening. Gives it a distinct mixup from the usual paladin trope.
oh do not get me wrong. I belief that Paladin for All races are possible. the 4(5) i mention just need a little more Lore added for them to work.
While Orcs could just have their newly added priest lore be build upon.
And with most Alliance races, they could just extend pre-existing lore.
but yes Alonsus Faol will most definitely be the one who leads the Forsaken Paladin order.
If gnome paladins happen they’ll probably (sadly) be added as (combat) medics instead of Knights of the Silver Hand, unless High Cleric Alphus will play a role.
World of Warcraft only allowed the Light worshipped by the humans to be spread towards thr dwarves and elves and somehow no gnome except Alphus picked it up in the hundreds of years they’ve lived alongside humans and dwarvew 
(a clear case of Blizzard once again bieng biased against gnomes).
https://wowpedia.fandom.com/wiki/High_Cleric_Alphus
https://wowpedia.fandom.com/wiki/Gnomeregan_Medic
Used Light magic during Operation: Gnomeregan.
https://wowpedia.fandom.com/wiki/%22Doc%22_Cogspin
The gnome priest trainer, uses Light, wears plate armour.
Feels like lacking writing at this point. I am all in for a more technological take for Gnomes specifically, but I feel the door is open for some sort of syncretism between their philosophy, self improvement, and something of the Light.
Seeing what you’ve linked, it would still seem that gnomes are (impossibly?) secluded from the rest. I will see to add this specific take tomorrow.
Night Elves already have paladins. They’re called Watchers. Their origins are extremely similar to human paladins, a handful of the priesthood swapping cloth for plate armour and given a new role, and they fit the bill of “holy warrior” perfectly.
I will say, though, that a lot of the ideas here are a little… Off-theme. If you make Forsaken paladins all about the void then they aren’t exactly paladins, for example.
I wonder what Blizzard will add as lore for void elf paladins. It is really with them that it will be necessary to make an effort because a void elf who uses light does not exist for the moment.
Paladins with an upper-case P are infused by the powers of the Holy Light, paladins with a lower-case P are simply plate clad holy warriors. The Silver Hand consists out of the former, Blood Knights and Sunwalkers the latter. Some Blood Knights wield the Light through faith, like Liadrin, others draw on the Sunwell to wield the Light, but they are not infused by the Sunwell’s energies.
Only Silver Hand paladins are so infused with the Light.
And even then, it’s iffy. The same book that confirms the tradition of the Silver Hand to infuse their paladins with blessings and holy weaponry has Tirion reconnecting with the light and regaining his powers only a few pages later after being excommunicated and stripped of all of those blessings and armour.
I do not think they need to be light users within the lore to take the same gameplay in the game. Some imagination or visual adaption is due.
Adding to this, Darkspear/tribal trolls have their holy warrior equivalent as well.
Shadow Hunters are culturally considered paragons and spiritual champions of their people and they’re imbued with the powers of the Loa, as well.
The fact that Zandalari had Prelates and not Shadow Hunters was a distinction raised in the old Mists of Pandaria lore, where the way of the Shadow Hunter is closer to the ancient roots of the troll race as a whole.
The shadow hunter figures could tie with Vol’jin having merged with Rezan and becoming a referential loa too, perhaps enabling a more Light-of-the-Loa oriented stuff. Seems a bit much to me but it’s not impossible.
It’s important to draw the distinction that their blessings are not “the ability to wield the Light”.
Their blessings make them have almost endless stamina, immunity to disease, and arguably super human strength depending on how you interpret the hammer and the “divine fire burning in their veins”. That’s what separates them from warrior priests i.e. clerics like Mara Fordragon who was actually just a Priest who picked up armour and a shield to protect the refugees of Stormwind during First War in their escape.
Tirion thought that by having his blessings removed from him, he would also lose the Light. And that crisis of faith and doubt did end up costing him that. But as he regained his faith, he reconnected with the Light and came to the realisation that Uther didn’t cut him off from it – but he never regained the blessings that we officially know of.
Paladin with a capital P specifically requires the ritual and Tirion ceased to be a Paladin. But he never stopped being a holy warrior. It’s plausible that he might have had the ritual recreated under the Argent Dawn/Crusade, but that remains conjecture.
I’d also make a case that the blood knights have a much more martial and regimented culture than other paladin orders.
I’ve added some of the takes discussed here. Please do not hestitate to speak further.
Why would it be more martial than other holy orders, though?
I’m not sure if it’s been mentioned but blood knights are taught faith in themselves and their own ability that is as similar to the secular “it’s just magic” view as its gets. Surely with its own cultural baggage but I won’t extrapolate too far lest I write an essay more fitting the headcanon thread.
We know little of the Sunwalkers as an organisation, the Vindicators are probably on par with the Blood Knights in in militarised martial culture, but the Silver Hand? They’ve always had a big focus on being civil servants first and warriors second.