I think the fundamental difference here is that NPC expansion is very methodical and process-oriented, and this process is highly documented on these forums. I can't speak for multi-cultural organizations, but my understanding was that they are typically not nearly as constrained by the school being "open for expansion".
The goals for NPC councils are typically such that most organizations are at some kind of size parity and are all strong enough to survive. NPCs at many schools (including many in California) invest in very expensive housing infrastructure, which demands large enough memberships to make the entity successful over a long time period. These organizations often don't have the luxury of remaining small compared to the other organizations on campus. Coupled with a long history of unanimous agreements and highly coordinated recruitment environments mean that NPC groups undergo an extensive mutual selection process for colonization. You won't even see that kind of process with IFC fraternities.
I think the first step for you is to just research the councils at the target schools, see which organizations currently exist, and look at demographics for those schools to see if they would likely support the addition of your group.
As for council structure, I would bet that you'll see many variations and many structures among schools.
Examples:
UCLA has an Asian Greek Council, an Interfraternity Council, a Latino Greek Council, a Multi-Interest Greek Council, a National Pan-Hellenic Council and a Panhellenic Council.
http://www.greeklife.ucla.edu/
UC Berkeley has IFC, Panhellenic, National Pan-Hellenic, and Multicultural Greek Council.
http://www.calgreeks.com/
USC has an Asian Greek Council, Multicultural Greek Council, Interfraternity Council, Professional Fraternity Council, National Pan-Hellenic Council, and Panhellenic Council.
http://www.usc.edu/student-affairs/g.../councils.html
Stanford has the African American Fraternity and Sororal Association, the Interfraternity Council, Intersorority Council, and the Multicultural Greek Council.
http://studentaffairs.stanford.edu/r...ife/fsl/houses
SDSU has the Interfraternity Council, National Pan-Hellenic Council, College Panhellenic Association, and the United Sorority and Fraternity Council (for culturally-based organizations).
http://go.sdsu.edu/student_affairs/s...eadership.aspx
Those are only the first five schools I looked up, and you can see that they all structured themselves differently from one another. I'm sure the next five schools you look up will have five more structures.
Good luck.
ETA:
I think "Greek Unity" events will also vary school by school. Greek Week combines organizations of all councils at UCLA, but I can't speak for other schools. Chapters are encouraged to have mixers between councils, to varying degrees of success.
Additionally, I wasn't familiar with council organization at east coast schools, so I did a quick search on Alabama, Syracuse, Vanderbilt, Georgia, and Florida. They seem to be arranged very similarly to west coast schools - a variety of councils, many with a Multicultural Greek Council of some kind.
