Thank you purchasing a Toro midsize mower.
The battery has a vent opening on the top of the battery to prevent the battery from building up internal pressure. The battery is continuously venting even when it is not being used because of the chemical reaction of acid and lead. This liquid can get on to metal and create the white appearance once dried. The white appearance can be neutralized with baking soda and water. The metal hardware is not structurally affected but the hardware can rust once washed. To lose a small amount of liquid over time in a battery is a normal process and can be topped off with distilled water. From the photo you provided I can see a sheen in the opening of the battery vent. It is hard to determine the source the hydraulic fluid on the frame. Maybe if you lift the corrugated hose covers you can determine if the leak is hidden. The photo also shows a trail of liquid from the battery down to the wheel motor area. It's possible the moisture on the frame is coming from the battery not the hydraulic system.
-The Toro Company