Shoes is a keyword. Sellers will put it in there to draw more views of their product and broaden the selection presented to the buyer, even if they arent shoes. Waterproof oversocks might be a decent option too.
Did you not look very hard? I found many options with a simple google search.
OMGear Water Socks Neoprene Socks Beach Booties 3mm 5mm Anti-Slip Wetsuit Footwear Fin Swim Sand Proof Socks https://a.co/d/5yDRc7P
Any age. We did a day at MK with my daughter when she was a year and 9 months old and i'll never forget the look on her face and her reactions when she met Mickey the first time. Plenty of rides she could do too. 40 inches is the first major benchmark for the majority of rides. Only a few are higher - RNRC (48), Space Mtn (44), FOP (44) and Everest (44)
My comment was in regards to the Giant Wheel, not Boomerang.
Last I knew they ran 2 on Tantrum pretty consistently. ROS is the only one without a second train available I believe.