redraw a series of pencil sketches into digitally painted artwork

I have a set of three pencil drawn scenes, depicting clinician locations from the mid 18 century, that I need digitally painting with details added such as authentic Venetian characters, props, et cetera. The artwork must be rented at high resolution, ideally plus, and I would like the final delivery files to be layered brackets ideally, Photoshop PSD files) so did modifications could still be made after delivery