Hello Erin and thank you for bringing such great questions to the Disney Parks Moms Panel.
Firstly I'm delighted to know you have a magical upcoming stay planned at Walt Disney World Resort and I'm happy to share that in the past when our own extended family members (who were
not Guests staying in a Walt Disney World owned & run Resort) came to visit us they did not experience any issues when arriving at the Resort hotel security gate. As is usual, all Guests arriving at Walt Disney World Resort hotels are asked to provide valid photo ID, plus it maybe helpful if your visitors could also give your family name to the Disney Security Cast Member.
Secondly I can just imagine how excited your darling little nieces must be about their magical trip! While Guests must be aged 14 years or older to enter unaccompanied a Walt Disney World Theme or Water Park,
Walt Disney World Resort Park Rules do state that to board an Attraction Guests aged up to 7 years old must be accompanied by another Guest aged 14 years or older. Disney Cast Members are simply
Wild About Safety so for further general Attraction advice I would seek the opinion of the Cast Member assisting at the time of entering the Attraction.
If I can help sprinkle any extra pixie dust onto your upcoming plans to visit Walt Disney World Resort please pop back to ask me another question.
Have a great Disney day.
~ Jane