Sorry we couldn't come up with something, it doesn't make sense. I'm out of ideas at this point.
Don't know, I'll have to go look. It might simply have been overlooked.
There's no separate volume control for that unfortunately. If even vanilla is too loud, you might see if you can find something that drops the volume on weather sounds via the attenuation settings in the sound objects. We don't edit those, only NI has extra ones added since they didn't exist before.
I don't see why not provided OBSE has a method for changing cloud speed. That's up to wrinklyninja though since I've only just begun to get a handle on the weather script.