Another speculation about Vulpera priests: I wonder if perhaps their priests might be sun-worshipers (sorta like the Tauren, but perhaps with their own fables behind it) who unknowingly are calling upon the Light, or if they’re ICly medics? I could see the “standard” Vulpera priest going a number of ways.
But yeah, as far as I understand, Loa - like any other deity in the setting from what I remember off the top of my head - can really be worshiped by anyone. It’s just that Trolls are their most common demographic, and the worshipers we have the most records on.
There are countless Loa, but many of the most powerful ones are the most frequently followed and well-known. Many Loa are much more obscure figures. They fall into the Wild God category, which is the same category that creatures like the Ancient Guardians, August Celestials, and others are a part of.
It’s all a little complicated, at least in my opinion, so don’t feel bad if it gets fairly confusing to keep up with at first. It’ll more than likely take some trial-and-error to figure out what concepts you feel are the most “right” for your character, so don’t feel afraid to tweak things as you go if you feel some ideas don’t work out or that something else that interests you could be added for flavor. No ideas are perfect at conception! It takes a lot of re-working to get it just right.
Most importantly: If whatever you go with is not fun for you to write for, then it’s going to be extremely hard to keep wanting to roleplay with that character, so do what feels the most engaging for you and find ways to make it work!
I really recommend combing through some resources about the Wild Gods and Loa, what lore of Vulpera that you can find (including re-reading quest text from Vulpera NPCs on the wiki), how other priests within WoW’s lore operate culture-to-culture, and perhaps even some real life resources for inspiration. Sometimes just finding a particular detail or two in your research gives you an “a-ha!” moment for what you feel would be perfect for the character. It’s less about obsessively trying to commit all the lore to memory, and more about just trying to find inspiration that helps all the pieces click together.
Also, just starting simple and testing the waters by going ahead and roleplaying with some other people can give you a better idea of how you’re going to play the character personality-wise. Sometimes it’s easy to plan a character out on paper, but when you actually jump into roleplaying them, the character turns out to be someone completely different when put into a more natural environment where they’re interacting with other personalities. So if you’re not particularly committed to any one idea for the character, just playing things by ear and adding details on one at a time as you go can be very helpful if you’re feeling a lot of uncertainty.
I do really like the concept of your character worshiping Jani, though. I could imagine that perhaps a priest of Jani could serve the loa as a caretaker of Jani’s children that he’s very protective of. Or maybe someone who cares for the poor and orphans, and has their healing capabilities blessed by the boon of Jani, who may approve of their deeds. Overall, in order to maintain the boon of Jani, I would think that such a character would have to adhere to all of the principals that Jani holds dear as like a personal code of conduct, and avoid breaking them lest they face the Loa’s wrath. There’s a lot of directions in which you could take many of these ideas! It’s really up to you how you want to do it!