Any item which helps your child float - yes - Water Wings, Life Vest, for a baby you can use a baby seat float with a parent (or person over 18) with the baby.
Babies must wear Swim Diapers.
On water slides - no Water Wings or Life Vests allowed.
I would also recommend only a child who can swim to go down a water slide - at least be able to dog paddle and tread water, to go down a water slide. Did I say tread water - a must do and be able to swim away from where the water slide dumps into the pool.