4e Bane is great. And there's a reason Mercer's using D&D cosmology in Critical Role
In 5e cosmology of course the elemental planes are contained within the Elemental Chaos. There's a huge amount of made for 4e cosmology (starting with the Feywild and Shadowfell) in 5e.
View attachment 268380
Absolutely agreed.
Absolutely agreed. My take on the Great Wheel is that what's actually there is the Astral Sea. with many heavens/hells/locations and many of them have short paths to many others. However there's one particularly famous and well-trodden route that goes round most of the biggest ones in order of alignment. This is the Great Wheel - but there are other routes, some well trodden and some not so much. (And if you do that the only non-4e cosmology left is the Etherial Plane).
Edit: And the actual paths on the Great Wheel do change. The people in Nirvana managed to engineer their own replacement with Mechanus on the wheel because they didn't like all the tourists and messengers tramping through.