The general situation seems far too messy and complicated for me, regarding lens compatibility. If it were a simple case of a particular Canon lens either working or not working with a particular adapter, then fine. One would know exactly what to expect.
Unfortunately, there seem to be various degrees of compatibility or functionality. One might think a particular lens autofocuses very satisfactorily with the A7RII and a particular adapter, then one later discovers it doesn't lock on Continuous AF, which could be frustrating in certain circumstances.
Or, one thinks a particular zoom lens autofocuses brilliantly, but finds that is not the case towards the maximum focal length where autofocusing is poor, or one finds that in dim lighting conditions, autofocusing is useless.