Betty, I'm so very sorry you find yourself in this situation. I don't know how useful it'll be but I'll share my experience in case it helps at all. Sorry it's a bit long...
I lost my son at 36 weeks just over a year ago, also due to a placental abruption. We have 3other children, who at the time were 8,6 and 4. They weren't able to see their brother after he was born, as it all happened so quickly during the night whilst they were asleep. Possibly in hindsight we should have brought them to the hospital to see his body the next day, but we weren't exactly thinking clearly at the time. They were very upset about never having met him, and we gave a lot of thought to whether they should visit his body in the chapel of rest. In our case, this was a good while later as we had opted for a pm so it was after that.
Dh & I went to view his body ourselves in order to make the decision, and it was then an easy decision: whilst his body looked fine - as in not a terrible scary thing to see, it just didn't look anything like he had when he'd just been born. The change was probably much more pronounced for us as 2 or 3 weeks had passed, but I suspect even after a short time that would still be the case to some extent. If our dcs had viewed the body, their only memory would have been of seeing an empty shell, that no longer looked like their brother. That was, tbh, how I felt about it at the time.
Whilst our children continued to wish they had met their brother, we felt so certain it was the right decision, it really helped me to deal with that particular part of their grief & not feel guilty.
So, I suppose I'm saying I don't think it would be terrible if you took your daughter with you - I don't think it would be traumatic in any way, but I'm not sure that would be particularly helpful either.
I can't help wondering from what you've said whether it's less about her saying goodbye and more about trying to make sure your dd remembers her sister? I know I would have found it very difficult if mine hadn't remembered their brother, even though I also wanted to take their grief away. If that's the case, and is where the question is coming from - I think, now being a year down the line, that our son's memory is kept alive by all of us, by how we see him as being part of our family. My dcs never met their brother, but they each have their own copies of his photos, and we talk about him freely whenever any of us want to. In your case, if you talk about her younger sister, and your photos are not hidden (I don't mean they have to be on the wall, just available in some way), she will grow up to not remember a time when she didn't remember, if that makes sense.
I hope some of my waffle helps a little bit. I'm sure whatever decision you make will be the very best one you can make at the time, and once again I'm so sorry your beautiful daughter died x