One way might be to use the artwork as an Opacity Mask applied to a reflex blue background shape. You find it in the Transparency palette flyout.
Always work on a copy when destroying artwork.
To make life easy remove any color swatches except the one you need. Once that is done expand any brushes or symbols.
Now go to Edit>edit colors>recolor artwork
Change where it says Colors: Auto to 1
Double click the small color bar to the right under "new" and choose the color you are recoloring to
Double click in the same area but to the right of hte black color bar, and set this to the same color
to the right of those same bars you just changed is a small context menue, change the options for both to "preserve tints"
I woud use the recolor art feature as well and choose1 Color art as the default