I am so sorry about what you are going through. I know how much you love Sprinkles and this must be frustrating. I'm glad you saw she was in a situation that was not the best for her and took her in.
I am also extremely relieved to hear that she is doin better right now. I hope it continues.
How long ago did you get her from your friend and when this happened was there a drastic changes in her diet? I know that that can cause serious problems sometimes, so could that be a possibility too? OR did she have these problems at your friend's house too?
Broccoli and Bok Choy are both things that I also feed my bunnies, but I do feed that to Jack & Rucy in moderation because if given too much it causes digestive problems in Rucy. (and i can't feed it at all to Bailey because of all her health issues, she reacts negatively to it)
Parsley is great! Do you have access to more "leafy" type of greens? Like Romaine, cilantro, dandelion... instead of using solid veggies as an equal part of the meal?
You can use celery but be sure to cut in small pieces because the strings can cause digestive problems. But again, if you can get more leafy greens that would be ideal. What selections do you have
Regarding the pellets, are the Lucerne ones Alfalfa based too? If so, then I think you are also making the right decision to cut back.