"As a student named Tom Riddle at
Hogwarts in the 1940s, he learned of Horcruxes through books in the
Restricted Section at
Hogwarts Library, including
Secrets of the Darkest Art, and sought out
Potions Master Horace Slughorn for further information about creating more than one, of which no book would have any record."
(Quoted from the wiki.)
Herpo the Foul was the first wizard to make a Horcrux. At some point after that, it was written into books, including the one Tommie used to start making his. Does anyone really believe that book crossed the world, down through the ages, and no one ever read it, copied it, used it?
Other books mention them, so somebody besides Herpo had to have made one and caused enough of a ruckus that at least one book on Dark Arts just mentioned the name and refused to say anything else about them.
So, given the sheer numbers of tales around the world of people that pulled X thing out of themselves and hid it outside their body, I find it hard to believe that a curse breaker like Bill doesn't know about "The Hidden Path of Immortal Life.", a series of ways to live forever by hiding your soul/heart/death/whatever in a container somewhere out of your body. I would assume that each method has it's own name, and curse breakers both love them and hate them with a passion.
They love them because people evil enough to use them are vain enough to use valuable things, beautiful things to store their death insurance in, which makes for great bonus pay when they bring them back.
On the other hand, you generally have to be a powerful mage to make it work, with an evil, underhanded, nasty habit of trapping everything within a half mile of your container, a fact that has killed more than a few curse breakers.
So, Bill will recognize the idea of the thing, even if he doesn't know this particular method right off hand, but he can find someone that can tell them about them.
I would find that far more likely than Skitter mastering Magic of any kind quickly. She's not stupid, far from it, but the idea that a single mispronounced letter can turn a first year charm into an intercontinental teleport summons of a buffalo and nobody tried to improve the new "teleport large masses" spell is going to boggle her mind.
Skitter: "Wait, wait, wait. Somebody accidentally summoned a buffalo, from either Africa, Asia or America and no one even thought about what that means? Was it alive, did it live long afterwards, how much did it weight? Can you choose to summon other animals by changing other letters, can you aim it at a target? Can you send it back, or send a different thing or person back? Holy shit, people, how do you ignore all the possibilities here? Are you that stupid?"
(Correction after double checking: if it was an actual buffalo, it was from Asia or Africa, if it was a bison, which is commonly called a buffalo, it was from Europe, Americas, or a dozen other places.
Still a remarkable feat, to summon 500 plus pounds of creature across the channel, via apparition, when most people can barely side along bring their kids.)