Alexander's efforts to unite all of the Scots, and his concern for their welfare, made him the standard for his successors to emulate.
I think 'made him the standard' means definition 11-13. Then what is 'for his successors to emulate'? Do 'for his successors' and 'to emulate' just modify noun complement 'standard' respectively? Does 'for somebody to do something' have its own meaning?