hk,

Your post is so very scary and sad.
First, how is your DD today? Is she feeling OK, anxious, is she eating? Any residual weird things.
The scary part after her first EPI reminded me of my DD's biphasic reaction during sesame anaphylaxis (not a food challenge). It happened after EPI, ambulance, ER and ER meds. The hives were so huge I could not believe they were hives. And yes, crazy scratching and yes, respiratory distress.
I think your instinct about the doctor is spot on and suggest you listen to it.
At all of our food challenges, we have two nurses constantly monitoring DD and the allergist is in and out about every half hour to 45 minutes. Available immediately if needed. They have EPI pens and emergency equipment in the room. Vitals are checked every 15 minutes. They are in constant communication with me and DD, there is no chatter in the hall.