Very sorry, OP, but I think you are mad to consider the name Pixie.
Here is a list of sayings I like to consider a name being used in. For convenience sake, I'm imagining your surname (or your DD's future surname) as Smith. Please substitute your real family name as you read these.
"All rise for Her Honour, Pixie Smith."
"The Prime Minister, Pixie Smith."
"Your psychiatrist, Dr. Pixie Smith, will see you soon."
And then I like to imagine the name with titles:
Princess Pixie, Lady Pixie etc.
And then I like to imagine the name on three different adults:
A normal weight person.
A very thin person.
A very fat person.
And then I like to imagine the name being called at a park with a whole bunch of children and dogs, and envision whether more children or pets will come running.
And I'm very sorry, OP, this is quite harsh but I think Pixie is an absolutely dreadful name. It's a nice nickname though, and I think it's very cute for a child.
IMO, Ottie is nicer as a name but still not quite right? Does your DH have any suggestions.