Whether or not a mill is an example of a wheel and axle is a matter of semantics. It certainly would contain examples of a wheel and axle.
A wheel barrow is one example
You could say a bike wheel is a wheel and axle. Also a doorknob is a wheel and axle.
Can opener
a doorknob
A cycle
yes of course
No, a pencil is an object used to apply carbon lead to writing materials.
No it is not.
yes
Yes.
No, a seesaw is an example of a "lever".