OK so the movement that Horace Mann supported was the educational reform movement.
1.- These 3 arrangements differ from each other, since the Amalgamation, is the mixture of different things, they may be cultures or races, the Assimilation is the process of adaptation of the immigrant to the receiving society. This acquires the culture and customs of the adoption community, disappearing their status as "different". To the extent that the immigrant adopts the culture of receiving society, this will admit you as one more member, producing its full integration. This theory has been strongly criticized, from the ethical point of view, but also by believing that the immigrant will adapt to the new culture, independently of its origin, race or religion. And Pluralism refers to the dominant trend is that neither natives nor immigrants want to lose their identity, and adaptation would occur through the adherence of all, to common principles of coexistence , being able to maintain at certain levels the cultural characteristics of each group and as long as the conflicts that may arise do not affect these basic principles of coexistence, which are those that confer a sense of community and avoid social fragmentation. The most common stereotypes are: Americans, Latins, African Americans, Chinese, they will be more or less frequent depending on the city where you live, Latins are a common stereotype in the northern United States, and I do not think they are harmful to any group, The harmfulness of something or someone does not come from their race, or stereotyping.2.- In my country we experience the 3 arrangements, amalgamation, assimilation and pluralism, nowadays, thanks to globalization, we experience all 3 in many countries of the world, in almost all countries there is a mixture of races and customs derived from foreign citizens, in many of them foreigners adapt so much to the culture that they are inserted very quickly assimilating it as their own, and in many others the different cultures struggle to maintain their origin and customs, giving way to pluralization.
