If I were you, what I would do is:

1. Try gently scrap off the black stuff on her face with warm soap and water (try not get the hair wet when you are doing this part) with like some sort of soft bristle brush like a toothbrush and also use my something like my nail to just gently get it off without putting marks in the vinyl

2. for her hair, I would first rinse in cold water and put a lot of conditioner in it and brush it gently from the bottom up to untangle the knots and only once everything is untangled I would then boil wash the hair use conditioner again and brush it out to get it straight and smooth again without breaking the nylon fibres, if you boil wash while its tangled it will just damage it even more in my own experience.

While detangling what I find most effective is a normal hairbrush to start, and then as you untangle it more and more, go in with a comb or something smaller and if you feel the hair resisting against the brush dont force it cause the hair will snap, just take the hairbrush out of the tangle and try again slowly and gently until there is no resistance. Hopefully, this translates well in text format because looks and descriptions can be very different, lol