Featured The 14th Nisan (A Preparation Day; before the Sabbath High Day) was not before a double Sabbath.

No. Per Mark 14:12-16 it was the first day of unleavened bread when the passover was being killed.

This was the afternoon before the morning of Nisan 14 (between 2 and 3, depending on what day the morning of Nisan 14 fell).

Mark was not alive during the exodus from Egypt.

Your argument that the Jews did not following Exodus as you interpret the instructions is meaningless. The Jews added laws to the Law, and we know when the pasdover was sacrificed, killed, and when people observed the meal with their families.

I question your discernment because you seem to think that the Jews killed the animal, bled the animal, sacrificed, had the ritual at the Temple, went home and ate their meals at one instant moment.

I question your judgment because you ignore what did happen in the 1st Century (the laws Jewish leaders added....those Jesus even mentioned.....to pretend they followed the Law perfectly.