> If I make a typo when using a value parameter in a function definition, can I accidentally introduce an extra value parameter?

No.

> If I make a typo when using a type parameter in a function definition, can I accidentally introduce an extra type parameter?

You couldn't introduce a new concrete type. You could introduce a new type variable, but the type signature would still have to typecheck, so it would difficult to come up with a non-contrived example where that would happen.