Ah, right as usual. Forgive me, I'm so high. You made look at Wiki for the last 30 minutes: Your first example is an epistemic fallacy your second example is the Masked Man fallacy, are all your examples considered Intensional Fallacies?
They are all in fact variations of The Masked Man fallacy, also known as an epistemic or intensional fallacy. This happens when we misapply Leibniz's law.
Leibniz's law states that two entities can be thought of as identical if their properties are identical. This of course depends on us knowing all the properties of the entity.
1.) Joe proclaimed Richard Bachman wrote the book "Thinner". Richard Bachman is a pseudonym for Stephen King, therefore Joe must be claiming that Stephen King wrote "Thinner".
Because Richard Bachaman and Stephen king share the exact same properties they can be though of as the same, however we would be mis-characterizing what Joe meant if we equivocate the two. We can not assume Joe is aware of the identical properties.
2.) I don't know who committed the murder. I do know who my mother is, therefore my mother did not commit the murder.
In this case we make the mistake of attributing our knowledge of someone as a property. My mother has the property of being known by me. The killer does not have the property of being known by me. Therefore they can not be the same person. Stated this simply it's an obvious error. But some people are swayed by the following argument.
God is the most perfect being imaginable. The most perfect being imaginable possesses the property of existence, as existing is certainly more perfect than not existing. Therefore God exists.
3.) My brain is made of matter which occupies dimensions like space. My consciousness is not made of matter and does not occupy space, therefore my brain is separate from my consciousness.
Our consciousnesses is like our brain wearing a mask. When we look at the masked version, we do not see the properties that are in fact identical to that of the brain. Until we can demonstrate that the mind has properties distinct from the brain, we can not say they are different. When we damage the brain, we damage the mind, which is evidence that they share identical properties.