That 20% was already owned by jews that had bought it with backing of rich Zionist jews around the world.
Haifa has not had 90% Muslim population after Ottoman Empire collapsed.
The 1922 census of Palestine, conducted by the British authorities, recorded Haifa as having a population of 9,377 Muslims, 8,863 Christians, 6,230 Jews, and 164 others. By the time of the 1931 census of Palestine, this had increased to 20,324 Muslims, 13,824 Christians, 15,923 Jews, and 332 others. In 1938, 52,000 Jews and 51,000 Muslims and Christians lived in Haifa