What dates were these organizations incorporated?

Suggest you try a search engine like www.altavista.com. Click Advanced Search. In the box labeled Exact Phrase, type in the name of one organization. The search results will likely include the home page of the organization. Once you get there, look for a section like "About" or something like that. A history of the organ. will likely be there. I tried Omega Psi Phi and Delta Sigma Theta. It looks like both started at Howard Univ. Dates of founding and/or incorporation are in the sites. This search strategy will probably work for the last 2 organizations, too.