Must have been a highly efficient inlet for a Mach 2 plane: Two traditional oblique waves; a fan-shock (also oblique); a shockwave off the lip that is normal and oblique depending on how far you are away from the lip, and a normal terminal shock.
Yes is was very efficient - 94.7% pressure recovery at M 2.0 cruise
So, isentropic would, in this context, mean that no shock-losses occurred at all?
In theory yes, but in practice there was a small loss.