Rank turners yes, but I wouldnt say they were B teams. England had Root, Cook, Stokes, Woakes, Broad, Bairstow, Moeen. Only main guy missing was Anderson who would have gotten nothing from those dustbowls. Far stronger side than the ashes squad IMO. BD were missing Mustafiz.
Australia had Smith, Warner, Wade, Handscomb, Maxwell i think, Cummins, Hazelwood, Lyon, and Okeefe. Only guy missing was Starc. Essentially the same side that trounced India in Pune. Bangladesh was missing Mosaddek that series.
Even SA who toured in 2015 - and we would have likely beaten them in a Test that series - sent everyone barring ABD who was on sabbatical anyways. Steyn, Philander, Morkel, Amla, QDK were all there. Maharaj missed out but I think he hadnt even made his debut yet.
B sides they certainly were not.