Stalin held intense and deep hatred for the jews. That's why he created the Autonomous district (not even a province) of Birobidzhan. He hoped that all the Jews of Moscow and Ukraine will migrate to that wasteland, which is full of swamps and taiga. To his surprise, only about 5,000 Jews actually moved to the district (0.3% of the Soviet Jewish population).
I condemn the apartheid practices done by Israel. But the Israeli treatment of their minorities are much much better than the treatment of indigenous minorities by Muslim Arab nations such as Egypt and Iraq. Is there a single Muslim nation in the world which treats the minorities fairly?
Madagascar and Uganda - no. Jews will be a tiny minority. Women in Uganda have an average of 7 children. I don't think the Jews will migrate there unless they can compete with the Ugandans demographically.
Alaska.... well Alaska will be much better under the Russian rule. Give Alaska back to Russia. The Russians are still cursing Alexander II for his bloody mistake. At that time he was so high on crystal meth that he decided to give away 70 million hectares of land for just a few bucks.