Where do the Jews call the 10th of Nissan a "Great Sabbath?"
The sabbath before Passover is called the Great Sabbath because, according to tradition and Jewish reckoning, the 10th of Nissan (the original day of selection of the lambs in Egypt occurred on a sabbath. The original killing of the Passover lamb took place on Wed. evening and the "high day" of the 15th took place on Thursday according to tradition and their reckoning.
Google it - as they say.
It seems that, as the Lord would have it, the same thing occurred exactly when the type was fulfilled by the Lord - our Passover.
Every event from that time of the birth of the nation Israel occurred exactly as the Lord planned it and was fulfilled in type exactly so.
Trace out the picture given to us in Exodus and Leviticus 23 and see Israel seemingly wondering about on the Egyptian side of the Red Sea prior to crossing over at night and being "discovered" at dawn on Sunday as they ascended.
You'll also see the open show of Pharaoh - which type was fulfilled when the Lord made an open show of Satan on Sunday.
Look also for the sanctification of the first born of Israel and the resurrection of the fulfilled types appearing to many in Israel when the resurrection of the Lord took place with His waving of those first fruits of the Harvest before God on the day after the Sabbath when "He" entered the Land God gave Him on Sunday as commanded in the O.T.
The Lord didn't have an "early" Passover meal at the Last Supper because He would be "busy the next evening dying for the sins of the world". It was the fulfillment of the ritual meal before Passover where all leaven was searched out and disposed of in the houses of Israel. (See the removal of Judas and the washing of the feet of the disciples and much much more.)
The Lord did not disobey the command of God by removing sandals from His feet and those of the disciples in contradiction of the command of God. The Lord and His disciples did not disobey God by leaving their house and somehow flaunting it by going out to the garden at midnight and praying.
etc. etc. The types are even more intricately fulfilled then these few examples when you look for them.
It does require the Last Supper being only the "preparation" for the actual Passover.
It does require that the events on Thursday be considered part of "all these things" referred to by the man on the road to Emmaus.
It does require a Palm Saturday rather than the traditional Palm Sunday.
But then - the difficulties are no where as numerous with this scenario than with any others.
Besides the other scenarios such as a Friday crucifixion miss the point of the types fulfilled by the Lord altogether.
To each His own I suppose though.