Reflections in cycles and other puns

Good afternoon,
Recently I’ve been working on a low poly render for the first time, but I’m having some issues. Here are a few straight forward questions:

  1. How do I change the cloud material so it does not reflect the grass? I don’t want green clouds ;).

  2. Am I making some obvious mistake to get those fireflies? I’ve most things on this list but nothing seems to even make a difference. Clamping wouldn’t even touch them.

  3. I am looking to make this into an animation, but the render time isn’t optimal. It’s about a minute, which isn’t bad, but when it comes to animation, I didn’t know if there was a specific way I could optimize the rendering. I have the samples pretty low to try to increase render time, but that’s producing a solid amount of noise. I’ve tried most things on this list but I don’t have a graphics card that can I can render from :(.

Any help is greatly appreciated. Here are some screenshots along with the render:

Here are the materials for the clouds and the ground: