If you make any changes to the object structure, keep the following in mind.
If you want the new fields or objects to appear on the MIDM, make sure to add them to the first section of midm.xml and to any of the page definitions later in the file (this includes search pages).
If the new fields require normalization, parsing, or phonetic encoding, define the new structures in mefa.xml.
If a new field will be used for matching, add it to the blocking query used for match processing as well as to the match string in mefa.xml.