There are a couple of old schematics around, but you won’t find them by searching “schematic” because nobody really talks about them. If you search “driver” and find one you like that is uploaded to OSH Park, then you can download at least the source of the PCB, from which you can reverse-engineer a schematic. In some cases, members also upload schematic files and other relevant info about the driver to OSH Park. I have a few drivers up on OSH Park myself, but I never took the time to upload anything except the PCB source for manufacturing. If you’d like, I can give you an old Eagle PCB file of mine. But there are better driver files available, honestly.
As for modes, you will need a firmware, which you can find around here also. Fortunately, they are easier to get, since ToyKeeper has a repository of quite a few of them, HERE <<<