Yunji,
Thanks for listing the different treatment options and modalities for PTSD related nightmares. As clinicians, we want to target the symptoms in a pharmacological way, there are many therapy modalities that the patient can engage in to also help reduce those nightmares. However, as you've listed, the data is limited. I'm hoping for future research and sufficient evidence to help target those with PTSD related nightmares.
In regards to image rehearsal therapy, a study shows that the residual nightmares and PTSD symptoms may help, but after undergoing a trauma-focused PTSD treatment (Lu, Wagner, Van, Whitehead, Boehnlein, (2009).
Reference
Lu, M., Wagner, A., Van, M.L., Whitehead, A., Boehnlein, J. (2009). Imagery rehearsal therapy for post traumatic nightmares in U.S. veterans. Journal of Trauma and Stress, 22(3), 236-9. doi: 10.1002/jts.20407