UESP is good for gameplay. The Library is better for lore, as you said.
The wikia........it's on the verge of fan fiction.
TESWikia honestly said Titus II, emperor 160-odd years after Titus I and unborn as of the novels, was Attrebus' brother. Double-you, tee, [censored]?
Sload are apparently the major leaders of Nirn's soap industry.
I assumed it was made from rendered Sload fat. They have a lot of it, according to what little of them we've seen.
And yes, their flatulence can be used to fly to the moon.