Let me clarify that I am not defending anything, I am just trying to set the record straight as to JW beliefs. The outline of the Memorial talk shows that the JW version is that the Memorial is a separate celebration than the Passover and that it was instituted after that celebration; this is the direct quote:
Jesus instituted the Memorial of his death with those with whom he made a covenant for his heavenly Kingdom, the members of which are limited to 144,000 (Lu 22:28-30)
Once a year on the anniversary date.
This would also be consistent with the fact that the Lord’s Evening
Meal was instituted on the date of the Jewish Passover, a yearly celebration that no longer had to be kept by Jews who had become Christians. Reasoning page 268
Going by your bullet 1 it seems that you agree with the idea that the Memorial as observed by the JW was a separate arrangement:
1. The Memorial/Lord's Supper/Eucharist was indeed instituted by Jesus.