Yes, ORMMA defined a number of methods and events that were never became part of the MRAID specification. ORMMA started first, almost 5 years ago, and you have found the original code group and discussion forum. I keep it open because people seem to find it on Google as a place to ask MRAID questions.
MRAID version 1 was released in 2011. It including a small subset of methods from the original ORMMA spec. When MRAID version 2 was released the following year, we disbanded the ORMMA group and fully endorsed the IAB standard.
At this point, I only know about SDK vendors implementing MRAID, including the original ORMMA members. So I'm not sure that it's worth it to focus on ORMMA details.
Thanks,
-Nathan