I believe they are. We just returned after our first trip. Right next to the Meadows main pool is a junior water area with lots of fun splash areas and also a very junior tot sized pool. Of course, in all cases you must attend you're very young child for safety.
The Disney life guards are always present and walking around the pool. They can help guide you.
I don't know what the official policy is, but it seems like sometimes it depends on the lifeguards who enforce it. In the past, I've seen lifeguards say no to things that other LGs haven't. Doesn't TCD have a photo of the pool rules here somewhere?
It is probably going to depend on the lifeguard but if it's just a baby float and the parent is standing there, it should be fine. Floats become a problem when there are too many as they can block visibility in the pool if a child is under the water struggling, which is why most no longer allow them.