Wedeln - more or less right, I think, except for the spelling. It was the original technique for linked short-swing turns. To be more specific, it favored sliding the tails in a "wagging" motion, and a fairly hard check in a "reverse comma" position. Less specifically, in my youth the term was, so far as I remember, in widespread use in a more general sense to refer to short-swing turns in the fall-line, however executed. It was really a sort of general term of approbation. If you wanted to describe how good a skier someone was, it was a matter of placing them along the progression that went something like: stem turn - stem christie - parallel - wedeln. Saying someone could wedeln was approximately the same as saying he was an expert.
Jet turns - seems more or less right. Most generally, it referred to a turn in which you exited with your weight significantly back of center. Some people used it more specifically to refer to something that Killy either did or didn't do, depending on who you talked to. Keep in mind that -- it seems to me -- most analysis then was done by looking at single still photos, so it may not have been all that accurate. The mental image in my mind: picture Killy coming out of a turn, the whole ski (or most of it) off the snow, with the tip above the tail, his thighs nearly parallel to the snow. Whether any top-level racer was ever in a position like this for long, or in anything other than an unweighted state is open to discussion. Another iconic image: the woman with her shirt open in the "Keep Those Tips Up" Lange poster. As for how it was practiced by the hoi polloi, my memory is similar to pheft's. Some serious hot-doggers actually were fairly successful at turning on their tails. For everyone I knew, it was invitation to do something awkward and ill-advised that left them lying on the ground with alarming frequency.
Avalement - Something else entirely. It means "swallowing" in French (or so I have been led to believe). It was widely discussed in "How to Ski the New French Way," as the secret to life, the universe and everything. Basically, so far as I can tell, it refers to some amalgam of absorption and down-unweighting, though -- as with most terms -- it depends on who's talking.
Super Parallel Turn - Never heard that one before. Sounds like a marketing term someone invented to sell books with a "New!" ski technique.
Banked Parallel Turn - Doesn't have any specific meaning to me, other than the obvious.