My last reversal was much easier to recover from than the original operation to insert the stoma even though I was cut down the middle for both. Most people have the reversal done through the stoma hole so there is even less pain involved. Hopefully this will be the case for your daughter.
It seems like yesterday that she got the stoma and was having problems with dehydration. Maybe the surgeon feels that she would be better off without it for this reason as well as preventing adhesions. I'm sure he is doing the right thing.
I lasted less than a year after my last reversal before I started having problems again. I had that stoma for a year. I think the less time you have it the better, depending on why it is needed in the first place of course.
Good luck with it all and give her a hug and best wishes from all of us,