Your client is lucky to have the kind of support and expertise you, your teammates and the community are offering her. I guess the first order of business would be to supply her with guided imagery or relaxation exercises that would help her settle down and self-regulate, should the EMDR work trigger her, or should she run up against one of those aggressive outbursts. So for this, the General Wellness might be good; Peter Levine’s Healing Trauma might be another gentle, effective place to start. Our Anger & Forgiveness or Healthful Sleep could also be a help.
It’s not clear to me from the information given here whether she’s developmentally disabled as well as severely traumatized, and I’m not sure if there could be a second order of business. Our Health Journeys Relaxation & Wellness and our Healing Trauma imagery are definitely geared to build up a strong and stable core, but they can be emotionally evocative too. If she’s at a point in her treatment where she can tolerate and/or contain her feelings, and it looks like she’s building a real base of self-control and self-soothing ability, then you might want to have her try one or both of these.
Suzanne Scurlock-Durana’s Healing from the Core can also be a big help with this. And if her treatment with EMDR reaches a point of diminishing returns, you could see if she can switch to EFT and proceed from there with a related but alternate technique that some say can be less triggering than EMDR.
Best of luck and I hope it goes well!