Oh, poor woolie! I went to sleep last night before hearing about this latest problem. I hope you decided to give up and get some sleep before tackling this beast.
The biggest problem with soot is it just keeps transferring...clean one surface, then turn around, and somehow you've rubbed it again and it's all dirty again. The thing is, with each pass, the layer gets thinner and easier to clean. I don't know what's going on with the fireplace to suddenly start spewing the soot, but block it off until you can get a handle on it so it doesn't continue making a mess.
For everything else, just work on it slowly. Patience is your friend here. You're going to have to clean everything multiple times before you get it all up. As recommended, vacuum everything you can multiple times to get up all the loose dust you can before starting in with washing things. Once it's time to switch over to cleaners and scrubbing stuff, you're going to need a large bucket of water or a LOT of cleaning cloths/rags, because every time you pass a cloth over the surface, you'll need to rinse it or change it so it doesn't smear what's already on it around the next part of the surface.
If there's anything you can just take outside and hose down, that'll be the easiest to clean.
The clothes you'll have to wash a few times each, so it'll be a slow process too. Each wash will get them a bit cleaner. Start with the dark clothes, as it won't seem as dreadful with those, because if they aren't 100% soot-free, it won't be as easy to tell. Then work on the light colored stuff and whites. You can let the whites soak in bleach solution overnight after most of the soot is out to get the remaining discoloration out.
For carpets, you might need to rent a more commercial grade carpet cleaner to really steam out those stains, same for any upholstery. Oh...look in the phone book and see if there's someone in your area who specializes in cleaning after fires...they might be able to get the more stubborn stuff out and know some additional tips and tricks for cleaning up soot.
I think you better give Kia a call too...this job will take reinforcements. Maybe ask over the neighbor whose kitty you were out helping out of the tree...maybe she'd even bring over her kids...kids are a good source of elbow grease when you need it.
Good luck. I know this is probably even seeming worse after having such a rough day at work too.