Hi. I'm still around. Happy to explain the process for you. All of the drawings are hand drawn on water color paper (Hammermill 300lb) with colored pencils (prismacolor). Then I scan them into the computer and do some edits in Photoshop. It's not a lot of editing. Mostly color corrections/some shifting of shapes/cleaning up specs and scratches/etc. aa needed, and eliminate the background to be transparent. Most later packs have pixel-style versions that are just edits in photoshop and a program I used called pixatool (also available on itch.io).
I should make a walkthrough video sometime.