On hiring artist, I don't know how much they cost.
But I know how fast Europeans Comic book artist are, and how close to their public they are (having more than 50 hardcover comic books with full page drawing from the artist).
The illustration in a book like FCTF, could be done in a week if the author is working on something else.
So, given that you have access to french and spanish speaker, you should be able to find an affordable and quick artist, and if you want the extra thing, you might hire a colorist.