SHIKI knew about the 3rd personality
Azaka is bisexualLess of a WMG and more of a heavy implication, given her Origin. Her incestuous feelings simply push this (and who knows what else) further in the background. Also...
Azaka and Seo Shizune will have a relationshipThe vision Seo had when meeting Azaka at the end of Mirai Fukuin isn't just of their friendship, but of a future relationship. As soon as Azaka gets over losing her brother to Shiki, her friendship with Shizune will grow to be much more.
...and Azaka will end up being jealous of her own brother when she falls for ShikiBecause it's obvious the poor girl can't get a break. Expect the Harem Solution to be among her proposals...
Mikiya saw her whole relationship with Shiki and even her daughter, if not most of the events of the seriesMirai Fukuin reveals that Mikiya does have minor powers of clairvoyance. He can see an hour or a day in the future. However, while Seo Shizune finds herself burdened by this power, Mikiya reveals how he dealt with it: by pushing his power further rather than trying to suppress them. The Distant Finale and very last portion of Mirai Fukuin is called a Preface precisely because it's the first serious prophecy Mikiya saw while experimenting with his powers, well before even meeting Shiki.
Touko has Mystic Eyes of Appearing to Be Extremely RudeShe treats them like split personalities, which plays even more to the series' theme (Mikya/Azaka, Shiki/Shiki), but the reason she appears to be much more rude without her eyeglasses is because of the influence of her Mystic Eyes. She's actually the same both ways. This might also be the reason why Cornelius Alba gets so pissed at Touko: he's under the influence of her Eyes, and finds her to be much more rude than she actually is.
Some of Touko's dolls have physical differences.Hence her changing appearances across media.
Tomoe's dad was the one who ran over Shiki.And hence how he got involved in the whole traffic accident thing. Not very plausible, but it would make a rather amusing coincidence.