What aspects of the Passover ceremony reflect compassion for the death of all Egyptian first borns during the events commemorated?
The question may be better served under the perspective that the compassion was for Israel who for 400 years were beaten, raped, killed, starved, objectified, disrespected and treated more like cattle then people.
The compassion was that the Egyptians had 400 years to turn from their idol worship and have compassion for those they enslaved. To see them as people who should have had basic human rights.
A slaves life in Egypt was no more valuable than a dog, they could be killed without as much as an explanation. The death of the Egyptians came as a result of a judgment by God who knew the hearts of the Pharaoh and the Egyptian people. It was justly merited as was all the judgments of God on those who would perish under the sword of His judgments. Then, now and in the days to come.