Was Jacob's son Joseph cremated

No. According to the Old Testament accounts, Joseph had placed the children of Israel under oath not to bury him in Egypt (Genesis 50:24, 25; Exodus 13:19), so his body was embalmed and placed in a coffin when he died (Genesis 50:26).

His body was ultimately buried in a plot of land in Shechem which his father Jacob had purchased long before (Joshua 24:32; Genesis 33:18, 19).