(Yes, the most annoying glitch in the history of Brawl, I'd LOVE for THAT to be hacked out)
I agree that grab stock trading in general should have a universal name. However, I think DK's is a different exception, not so much because he has to use his regular grab to do it, but more importantly because it cannot be triggered from the air, while falling, which is the most common way to execute any of these techniques. Also, no one should really die from DK jumping off the edge, merely from him throwing you into the stage, and you failing to tech, and DK can recover from this, so it isn't really stock trading at all.
There are slight differences between some of these as well. Diddy can jump off of you, performing a gimp without dying. Kirby can spit characters under a stage, and fly to recovery. Bowser and Ganon don't have abort options once they start descending, etc. However, I think the common idea behind these techniques is that you use a special move to grab an opponent in midair, which enables low percent kills due to falling, and can result in trading a stock for a stock. That being said, I think only one term is needed, because players can differentiate by simply naming the character they are using to do this with.
I would say "Grab RELEASE gimping" is a better name for the term we were discussing before, and for this "Special Grab Gimping" is a suitable name, since ALL of these techniques utilize a special move that is a grab to gimp the opponent. GRG and SGG anyone?
One saying referring to D3's inhale would simply say "D3's Special Grab Gimp, or D3's SGG."
I'm conflicted, because Inhale-cide (what I commonly refer to it as) is actually simpler to say, but it's not like we're stopping the community from nick-naming individual moves and techniques. and I think Special Grab Gimping is a decent name for it., and that abbreviating it into SGG does ease typing considerably.
Also, for D3's chaingrabs. When he "infinitely" CGs against a wall, it should just be called a "Wall chaingrab" because it's pretty obvious what we're talking about, and not all walls remain interminably. This helps differentiate between his actually infinite cgs on some characters. Additionally, Ike can do the same thing, so it's better as a universal term in that sense (although Ike cannot begin his throw away from a wall and continue it into a wall, which is what truly make D3's WCG powerful.)