A lot of questions and big topics, but I'll try to answer a few.
Pome is a group that includes the Brazilian and Raja Puri, both of which sort of have an apple taste. Here in Hawaii the Brazilian we call Apple.
Silk is another group which includes what most of the world outside Hawaii calls the Apple banana, aka Manzano. In Hawaii we call it Silk Fig.
Locally people use Dwarf Cavendish and Williams as cooking varieties when they're green. They are both AAAs. So those are a couple examples where being just A doesn't mean you can't cook with it.
AAs I've had that range from extremely tart (Veinte Cohol) to extremely sweet (Kluay Khai) and can even be somewhat starchy when underripe, such as Rose.
I've grown 1 type of AS, Vunamami which is a hybrid of Musa Acuminata and Musa Schizocarpa. Would have loved to try it but it died
Plantains are all AABs and B is generally considered the starchy contribution to bananas, but there are ABBs that are certainly less starchy when ripe than Plantains are.
Group is distinct from whether or not a cultivar is AAA, AAB, ABB, etc.
Cavendish and Reds are all AAAs but are two distinct groups.
In general, the AAA types I've had tend to be much more sweet than tangy, and tend to have softer textures when ripe than those having some B in them.
So in general, lots of exceptions to trying to generalize about bananas!