Oh! I see what you mean, yeah, the lighting on the water droplets caused some weird effect from that angle. That's going to start bothering me now hahah.
About the billboards, thanks! Yeah, I tried my best to just have them at non-important/filler locations, for example, the 2 random pedestrians closest to the main characters are also 3d models, because they were too close for me to feel comfortable sticking with billboards. I did a similar thing with the cars, the closest one is high resolution, while the ones far away are very low resolution.
The idea of putting some lighting to force them to cast the shadows I want them to cast is pretty interesting! I'll try it out, thanks!