The above link talks about C.Lutea and its close similarity to C.Walkerii. Having browsed many different sites I am also kidda confused, but there seems to be a consensus that C.Walkerii is what was formerly known as C.Lutea.
As for using the leaf shape to determine any particular species, this is highly impossible because many plants share leaf morphological changes. I can attest to this because my old Wendtii 'red' and 'green' have totally different leaf shape and color to my new Wendtiis that I recently got. If you simply look at them you could not tell they are the same plant species. Also, the 'Lutea'(Walkerii) I got looks different than yours. Mine has a somewhat puckered leaf with spots on it. Sorry, man. I know I didn't help much; if any, I probably made you more confused
Hey Paul, that was a very informative article you posted, and good information in general. was not sure it was what they said it was because most of the luteas I found online had totally green leaves... this one has brown-reddish edges... but I see in the article you posted that there are some with totally brown-reddish leaves, so I guess that is not hard evidence for or against it being a Lutea.
I am not sure if the leaves are emeresed growth. They had it submersed at the store, and I had seen it there for at least a month before buying it... so I would think they are submersed growth.
I got the akadama soil from a friend, I do not think it is ADA aquasoil.