Hi there,
I was very happy to see your call, especially to learn that you are starting a book series, and I would like to express my most serious interest in your project. I'm a traditionally educated artist working as an old school illustrator for many years, lately mostly on children's book. I prefer to work by hand on paper, especially when it comes to children's books, as I somehow believe children relate much better to handcrafted pictures and what is more, that they should be exposed to real art from their early years. Assuming that you are looking or handcrafted art, I can offer variety of media, but my experience is that children's books authors prefer either coloured pencil or watercolours. I start with a storyboard in pencil and with pencil sketches which allows for limitless edits and which are to be approved before I proceed to colouring. I normally deliver high resolution scans, but I can also send the originals upon request.
My quote would cover for full illustration package including storyboard, characters design (you mentioned you already have the lead character), 24 one page full bleed colour illustrations, illustrated end pages, double spread cover art and some spot illustrations for the inside title page s should there is a need.
I have few samples posted at https://www.freelancer.com/u/ddimitrovska.html, but since I have several newer children's books, I would happily share more samples.
Looking forward to hearing from you,
kind regards,
Dusica