Not whiteoleander23, but I'll point out where I think clarification would be beneficial/she shouldn't have responded in a certain way.

I’m not a huge fan of unannounced surprises. Gifts are fine, finding something you think will help me, is fine, but please tell me about it. Give me fair warning, don’t just show up at my door and leave it, especially without telling me that you had afterward.
If you don't want her to leave things at your place without announcing, I'd make it clear that you don't want that no matter when she tells you about it. Saying the "especially without telling me that you had afterward" could be construed into "it's fine as long as I tell her afterward".

Was any of it abusive?

IMO no.

My having this disorder is not a topic of conversation for anyone beyond whom I choose to share it with, and it is my story alone to tell. Nobody in the family is to tell anyone about it, even if someone asks or expresses concern. Who knows and who doesn't know is my choice alone.

Very well written IMO, but especially after her response below I would really clarify what you mean and demand that she accept your terms.

You have no control over that. You do have control in stating when you say something to someone, not to discuss it with the rest of the family. Unfortunately dad and I are 1, and we do not keep secrets from each other, so you will need to keep that in mind

She should just have asked "Is it OK for dad and me to discuss things?" or something along those lines. Perhaps something along the lines of

Listen, I have told you, Dad and both sisters. So five people (including me) and my team know about my ED. No one else is to be informed of my ED. This applies no matter if you consider people close to you and worth sharing that information. It is not yours to share with people outside of Dad and both sisters. If info is to be shared with anyone beside Dad and my sisters, I will do so myself; you aren't permitted to do so irrespective of the circumstances, it is my body and my health. Thank you.