C) Mm, I'd wager to say that the Succubi and the Soulflayer are indeed Voident.

In fact, I'd even bet that the two named ones we've seen were once one of the spoken races and transformed in the voidsent creatures they are now.

It wouldn't be the first time this happened within the context of XIV's lore. For example, the story goes that Bomb Baron was once an adventurer who went around slaying bombs until he was killed by the blast of one and his soul was sent to the Sixth Hell where the Bomb King resurrected him as a bomb and sent him back to Eorzea to slay as many adventurers as he did bombs.

Lady Amadine (the named succubus of Haukke's Manor) was once a Duskwight woman who sold her soul in exchange for beauty. I can't remember if it's said anywhere who she signed away her soul to, but again, my money is on something dealing with demons and voidsent.

The soulflayer we run into in Tam-Tara is named Galvanth the Dominator, and the map of the dungeon as well as the 1.0 map of Tam-Tara show his tomb marked as King Galvanth's tomb and from what we know of Tam-Tara itself, it can be suggested that Galvanth has connections to Gelmorra. The Lambs of Dalamud, who we fight in the Deepcroft, are said to be ' plotting revenge against those who fought to prevent the advent of Dalamud, summoning any dark presence who will aid them to this end… no matter what the cost.' Through whatever means they're summoning the demons and creating magical barriers, I'd bet that they also somehow transformed Galvanth into what he is now.

Again, that's all speculation, but I think its pretty solid ground to support them being voidsent.

Bomb Baron: http://ffxiv.gamerescape.com/wiki/Bomb_Baron
Lady Amadine: http://www.finalfantasy.net/xiv/dung...-realm-reborn/