I wonder if EMP resistance was also considered, and if analogue computing could have offered better resistance compared to the digital devices of the time.
Impossible to know, though the use of nuclear weapons by an enemy was probably on everyone's mind, and diversity of redundant systems may have been applied in case some hypothetical enemy air defense came about during the lifespan of the aircraft.
Probably not a factor. There is a backup attitude indicator on the bottom right side of the panel. So a more modern version would have gone digital for the PFD (more options for extra indications) even with EMP risks considered and just kept the analog backup instrument.
Impossible to know, though the use of nuclear weapons by an enemy was probably on everyone's mind, and diversity of redundant systems may have been applied in case some hypothetical enemy air defense came about during the lifespan of the aircraft.