You've got so much going on, and this will not make added changes easier for either you or your daughter. My inclination would be to tell her you've decided to continue night nursing for X more weeks (whenever the stresses might be releived in your household). Here's my VERY abbreviated edit of a 2008 article on night weaning by Naomi Aldoort, an attachment parenting post. She makes some wonderful points that you might find helpful in thinking about this whole situation a bit differently:
"Many attachment mothers believe a child should never cry. This is not true, possible, or beneficial. Babies communicate essential needs through crying. Toddlers' wants are not always primal, and we cannot supply them all. Crying allows the child to release emotions, feel empowered, and move on. She can handle change when she is feeling loved and worthy.
…gentle night weaning will most likely include crying, she will always have your affectionate presence and she will benefit from the process. How long and how many nights she will cry depends on her experience with emotions. If she knows that emotional expression is valued for its own sake, she will only cry until she regains inner peace.
Support her transition with peace in your heart and she will see herself as capable and resilient. A well-bonded child will mirror you in how she responds to changes.
So before weaning, practice supporting your child when she cries. Minimize limits/frustrations, but when crying is unavoidable, don't give the the idea that crying must stop or that she can use it to alter reality. If she believes a long cry will change the plan, she will cry much longer. If she understands that you are meeting her actual needs and that crying is for emotional release, she will cry until she finds peace with reality. A secure 2yo surrendering a former habit is not traumatized, but self-expressing and being empowered.
ONE-STEP PROCESS: Prepare yourself in advance by imagining a future in which your child is contented. If you are secure in the rightness of your choice, your child will follow your lead. For some, just letting them know night nursing is ending "tonight" is enough. Your calm tells her it's no big deal, and you trust that she's ready. Nurse her to sleep, and reminding her that this is the only nursing in bed for the night. If/when she wakes, you can lie with her and hold her, with your breasts fully covered, and hold her lovingly until she settles.
Let her know that your understand she's not used to it yet, and you will hold her as long as she needs to cry. This usually lasts 2-4 nights, and lessens gradually.
8-STEP PROCESS:
1. Plan a special event (zoo, boat ride, visit somebody special). Explain the plan to your child.
2. Mark days on calendar with your child.
3. Talk about it with joyful anticipation every day. Respond to her questions truthfully, "It is for my sake so I can get more sleep." Don't pretend she has a choice when she doesn't. She can handle this if life in general is meeting her needs. Tell her she will fall asleep on the breast as usual.
4. If she expresses doubt/sadness, validate her: "If you wake up, I will remind you about no nursing. If you need to cry, I will hold you until you are ready to sleep again." (i.e., you'll support her emotionally.
5. When the day arrives, celebrate as planned, talking about the weaning with positive anticipation.
6. Breastfeed to sleep if that's your usual pattern, reminding her that this is the last feeding until morning.
7. If she wakes, support her tears without fear. She is struggling with change, not trauma. Keep the room dark, lie beside her until she calms. She will be done and go back to sleep peacefully, even relieved.
8. Avoid confusion by not breasfeeding in bed in the morning, or any time she's waking from sleep.
Ms. Aldoort claims this transition works in 2-5 nights, or if the child has learned that crying can change plans, up to a week. I did not need to do this with my co-sleeping daughter; the transition happened more naturally. But for an emotionally-volatile child, I suspect it could take longer. Still, I wonder if YOU are able to convince yourself that this is a positive change, it will ultimately be empowering for both of you. And if you are able to offer hugs and comfort without the milk, she may come to rely on those without nursing.
I'm hoping something in this approach helps. And I'm wondering whether your daughter might benefit from a pacifier or some of the chewing toys available for kids who need a lot of sensory stimulation. If you haven't looked into that possibility, you might check out this site: http://www.sensory-processing-disorder.com/