[Klaus]

 So do Nikon's lenses retain all their functions with decent AF speed with these adapters in practice? (at least on  the A7R II)

 

I'd say that a "good" AF performance is nothing you should hope for with these adapter solutions.

DSLR lenses are optimized for phase detection AF - thus essentially unidirectional, uninterrupted movements - which is why PD-AF is very fast (albeit not 100% accurate).

Contrast AF optimized lenses have to efficient for bidirectional movements because the camera does interim readings and the AF "over-shoots" a little before finding focus.

 

Thus it's more a question whether the AF is "good enough" with these adapters.