I think you've found it at SSR. It has zero-entry, a small slide for little kids, and a splash area.
Storm-along Bay is too big for little kids (in my opinion). Too wandering, too crowded. I like to keep it simple when the kids are really small (5 and under).
Poly has a great pool, too, althoug it's not
DVC. It also has a zero-entry option and a splash area. Come to think of it, Poly might be better, because there is a sandy beach right there for your little one to play on, plus the cafe is close-by.
OKW has a playground nearby and s cute kiddie-pool, but you feel disconnected from the rest of the area when you're there. The slide is enclosed so a toddler might not like it.
Wilderness Lodge is is nice, and there is a geyser that errupts every hour, but the slide might be too big for a toddler and the bathrooms are far.
I've only visited AKL pool, without using it, but it looks great for little ones.
We haven't stayed at Boardwalk yet, but that huge clown face on the pool gives me the creeps!
Hope this helps, if you have any specific questions, I'd be happy to try and answer them.
Susan