Please diagnose where I have erred in 4-6.
What have I misunderstood in concluding 1 to mean 6 (with X and Y reversed), contrary to the dictionary's 2?
Trying to decipher the back story was bit of a distraction. Even without a link missing between Latin “stands” and modern (roughly) “comprises”, does anyone doubt the logic is much more fatally flawed than if it simply fell foul of that etymological fallacy?
Next, it would have been better to try to reach a conclusion that fitted the facts, rather than vice versa. Since you put it that way, what you misunderstood was the semantics, the etymology and the logic.
Although they are slightly different grammatically, there was and remains no meaningful semantic difference between “consists in” and “consists of”.
Then, how does using '⟷' to represent semantic equivalence mean that '⟷' causes that equivalence, except to the extent that all aardvarks being quadrupeds makes all quadrupeds aardvarks?
1. X consists in Y ⟷ 2. X features Y in your diagram might just be short of axiomatic.
2. X features Y ⟷ 3. Y stands in X is worse than a non sequitur; it’s not even paradoxical, it’s just diametrically wrong.
2. X features Y ⟷ 3. X stands in Y would be the correct conclusion.
1. ⟷ 5. X stands in Y might, again, be just short of axiomatic, remembering that in 1., X consists in Y.
5. X stands in Y ⟷ 6. Y features X is another diametric error.
5. X stands in Y ⟷ 6. X features Y would again be correct.