Do the motivations and fears behind Enneagram have any scientific reasoning? Background

The Enneagram personality typing system defines set of motivations and basic fears for its nine personality types among people.

The system seems to be aimed at personal development of a person, and uses various approaches for the same (like one type integrating into other - which is essentially the person overcoming their basic fears using their motivations in a different manner etc.). For more info regarding the system, look here.

A large part of this system seems spiritual and based on very strange assumptions, but equally strangely - I don't know why or how - many people identify themselves with these basic motivations and fears in a way that doesn't seem like Forer effect - at least to me. The system is flexible enough that a person can identify his/her motivations towards one type and to some extent towards another type.

Questions


Are the motivations and fears for people listed in Enneagram typing system discussed in any other scientific theory about motivations among people?
There doesn't seem to be much of Forer effect taking place because people seem to identify themselves and "grow into other types". If we assume people are basically overcoming their fears doing so, what is the scientific term/explanation for such a process? 
Provided we have a flexible system here, people may develop in a more complex manner than by just overcoming their basic fears while integrating/dis-integrating into other type. What are people doing to themselves doing so?
The Enneagram model of personality (Riso and Hudson, 1999) has limited and mixed scientific evidence supporting it. One of the few studies reporting on the model's validity (Newgent et al., 2004) concluded the following in their abstract.


  Results of 287 participants were analyzed. Alpha suggests an adequate degree of internal consistency. Evidence provides mixed support for construct validity using correlational and canonical analyses but strong support for heuristic value.


Newgent et al. (2004)'s interpretation is consistent with my own reading of the limited Enneagram validation literature that exists. However, other validation studies do report their results in more unequivocally positive terms.

One such study claimed that they distinguished Enneagram types using a unique pattern of traits, values and implicit motives, thereby demonstrating that the Enneagram typology provides a way of describing the "whole person" (Sutton, Allinson and Williams, 2013). Another claimed that the enneagram typology appears to have diagnostic, prognostic, and heuristic value for the study of personality structure and dynamics (Wagner and Walker, 1983). 

These claims are based on simple statistically significant relationships, however, which is frankly speaking more consistent with the interpretation of Newgent et al. (2004).

References


Newgent, R.A., Parr, P.E., Newman, I. &amp; Higgins, K.K. (2004). The Riso-Hudson Enneagram type indicator: Estimates of reliability and validity. Measurement and Evaluation in Counseling and Development, 36, pp. 226–237.
Riso, D. R., &amp; Hudson, R. (1999). The Riso-Hudson Enneagram type indicator. New York: The Enneagram Institute.
Sutton, A., Allinson, C., Williams, H. (2013). Personality type and work-related outcomes: An exploratory application of the Enneagram model, European Management Journal, Volume 31, Issue 3, June 2013, pp. 234-249, ISSN 0263-2373. doi: 10.1016/j.emj.2012.12.004.
Wagner, J. P. and Walker, R. E. (1983), Reliability and validity study of a Sufi personality typology: The enneagram. J. Clin. Psychol., 39: 712–717.