Eyes Full of Light

Question: Are there no sun or moon gods among the Orisha? Were they not important to the Yoruba, or not prominent enough to feature as PC parents?

Actually, there really aren't. There is no Huitzilopochtli among the Yoruba gods, nor is there an Orisha equivalent to Artemis. It's an apparent omission that baffled scholars studying the religion early in the nineteenth century, especially the crazy ones who were convinced that the Yoruba religion must have grown out of the Egyptian one but who couldn't figure out where Ra and Horus disappeared to. The sun and the moon are certainly important, the way they are for most human cultures, but they don't have dedicated deities of their own.

One of the reasons the lights in the heavens don't get their own deities is that they're assumed to be the purview of Olodumare, the great father-god of the Orisha. Olodumare created sun, moon and stars and, as the lights in the vault of heaven, they are controlled and owned by him as the great primordial sky god. None of the Orisha can really compete with the big man when it comes to the affairs of the sky; even Shango is only in charge of storms, not the sky in which they rage.

The only myth we know of that directly involves someone other than Olodumare affecting the sun or moon is about Obatala, which isn't surprising since he's the second-most powerful creator deity in the pantheon. In that story, Obatala consecrates a sacred tree, turns it into sparkling metal and sends it off to Ogun to have it fashioned into a pot. He then puts the pot into a boat with his slave (possibly the same slave that once tried to kill him with a rock) and sends him to fly it back and forth to the earth each day, driving a solar boat for the rest of time. Based on that story, Obatala's the only one close to having Sun, but it's still a bit fishy - Ogun's crafting abilities are also involved and the slave is technically the guy actually doing the sun-driving - and we ended up deciding that it might not be quite strong enough on its own since the god has no whisper of solar connotations in any other story or cult practice.

Our only other possibility is Shango, who at some point during the religion's evolution was syncretized with a neighboring culture's deity named Jakuta who some scholars believe might have originally been solar in nature. Shango has of course lost that association almost completely at this point, but you could decide that he might have a few boons from the purview still kicking around.

It is surprising to see a culture that really doesn't do much in the way of direct veneration of the celestial bodies, especially sun-worship, which is nearly ubiquitous across a great number of different cultures. But every mythology is different, and in the case of the Yoruba there's no direct person representing for the sun or moon. Instead, everyone is covered in water, dirt and plants, and that's how the gods of western Africa roll.