Can a Storm Druid that gets the Air & Weather domains multiclass as a Cleric & gain the same two domains or the subdomains? I know that the druid or cleric "side" can not take the weather (domain) & storm (subdomain of weather), but can both classes have weather and/or storm & air and/or cloud? I see nothing against this.
What about domain spells? Could they put them in both classes' domain spell slots?