Are you offering anything to do this? I have a bilingual 16 year old granddaughter who could do this for you, but I imagine she might want something for her trouble?
A friend has asked me to find a "parent" who speaks Spanish. They've written a 300 word story for children, it's being published in the UK and she wants to see what it would look like in Spanish - but wants a parent's translation, not a commercial one. Freedom to change is OK so long as it helps the story and is child friendly.