Answer:
US immigrants created significant numbers of enclaves because of the hostility they faced (not the other way around). In the 1800s, unemployment levels weren't a significant concern relevant to this issue, and overpopulation worries weren't fully realized as a contemporaneous issue.
Among the other achievements of Reconstruction were the South's first state-funded public school systems, more equitable taxation legislation, laws against racial discrimination in public transport and accommodations and ambitious economic development programs (including aid to railroads and other enterprises).
