As Climates of Tamriel looks to have been abandoned I'm looking for a good replacement that not only does weather and lighting for vanilla Skyrim, but also for Dawnguard, Dragonborn AND Hearthfire. Any suggestions?

If you're not opposed to ENB, I'd give this mod a try. http://www.nexusmods.com/skyrim/mods/50065/? adds weathers, along with a lot of other nice features, like clouds that actually interact with the sun.