The grey wig you can dye darker grey with RIT or Dylon fabric dye in black.
The raven might be a good choice for a base colour in the Matilda come in the Raven which is a black blue.
Also Elmers make irridecent fabric marker that might give you nice highlighter over black
The white soild colour also works to tint a wig lighter.
Or if (and it's a big if) you have an airbrush handy you can use acrylics to add highlighters to the wig.