Mechanical washing machines were a thing before ww2. You might be better off finding one in an old barn and replacing whatever it uses (likely a crank) with a PTO you can link to a bike. Adapting a modern washing machine would likely be quite a bit more difficult.
a bit perhaps. but the drum is always connected to a belt that has a motor on the other end. and a washing machine is full of metal framing which you can drill and screw stuff to.
the hardest part would perhaps be to reenact the water cycle?