In Matthew it is stated that the priest went to Pilot the day after the Preparation Day to demand that guards be placed at the tomb. Would the priest go to see a gentile on the Sabbath, and thus be unclean? Just a question.
Pilate
Would it make any difference if it is a regular Sabbath or a High Sabbath? I don't think so
I’m not sure that there would be any strict prohibition against the priests asking Pilate to do something for them on the Sabbath. In fact, that might explain why they could not do it, themselves. On the other hand, neither would I be shocked if their behavior did violate the Sabbath; certainly, their demand to release an insurrectionist over an innocent already demonstrated that their religiosity was phoniness.