For your related question: You have it exactly right! There is a Record Type of "Constituent Alias - Match or Add" that is what tells IOM you want it to use Alias as a matching tool. The Value Type is the type of the Alias in that column. There is also "Constituent Alias - Add" that can be used when you just want to populate an Alias and not match on it.
Please let me know if I can be of further assistance.