Trey, how you move forward is your choice, but this is what I might do if I were you:
1) Set up a Foundation and call it something that makes it clear exactly what it does, something like "The Foundation for the Study and Preservation of Fraternal and Sororal Life." (Just an example.) Make sure this foundation gets 501c3 status -- this is important because you are going to want to solicit donations for the seed money for the project.
2) Recruit a good 8-12 board members comprising members of a wide variety of GLOs. Higher ranking members would provide more legitimacy for fundraising efforts.
3) Recruit a separate advisory board composed of various GLO scholars and possibly non-GLO members who have experience writing encyclopedias. They may or may not be the actual writers, but should be able to help guide the project academically and help recruit ground-level researchers and writers.
4) Recruit your volunteers/writers.
Basically, you want to have a sound structure for the financial/administrative aspects of the project as well as the research aspects of the project. There is more that can be said legally speaking, but no reason for extra words at this point.
