my granddaughter was a year old when she had hers. she was on a restricted diet before it (several days) and then we used miralax. all in all, what i found so sad was after it she hoarded food awhile, apparently thinking we ran out and she needed to hide it because she wasnt allowed to eat.
she slept most of the day of it, arfed a lot after it, and had a bit of bleeding from the biopsies.
but she didnt have the bad prep, i think they are too young and its too dangerous on their bodies.
i would check with the ped gastro and ask........they can easily have dehydration and electrolytes upset at this age. best of luck to you and her.