For the ripples in the water, there's one way to do it, but it's scriptless, and it's probably gonna be annoying to do.
1. Any maps with rain would either have to have a switch going on and off for the rain, or just always have rain and be seperate from others.
2. Make an animation sprite showing the ripples (just use white circles in different patterns, and make a few variations of them)
3. In the rainy map, but events in every (or almost every) space of water, and the animation sprite cycling.
I know it seems tedious and annoying to do, but it's the only solution I can think of.