I think too that the CEO plays a key role in the development of self-organization. Anyway this is not enough for it to emerge. I think the degree of empowerment, wich was usual before the transformation, the stage of the company's Feedback- and Cooperation culture, and the People-Development actions wich where taken already before the transformation are also crucial. It is a polemical topic if Holacracy really leads to higher performance and engagement, or if Companies, wich were already working in a high performing and high involving work environment are the ones who can run Holacracy with the best results. I would be serious interested in your research, as I'm involved myself in the Holacracy-empirical world. I know a really interesting model, wich analyses the development level of an organization (highest level would be Work 4.0) regarding the points: People, Organization & Technic. (https://de.wikipedia.org/wiki/MTO-Analyse) It is sadly only in German, but maybe you can use google translate? I will be happy to help and to hear from you.
Kind regards from Switzerland,