From these examples, I might guess that these mistakes fall into a variety of already existing categories, unlike something like the typical mind fallacy which tends to come down to just forgetting that other people may have different information, aims and thought patterns.

Assuming you're different from others, and making systematic mistakes caused by this misconception, could be attributed to anything from low-self esteem (which is more to do with judgments of one's own mind, not necessarily a difference between one's mind and other people's), to the Fundamental Attribution Error (which could lead you to think people are different from you by failing to realise that you might have the same behaviour if you were in the same situation as they are, due to your current ignorance of what that situation is). Also, I don't know if there is a fallacy name for this, but regarding your second example, it sounds like the kind of mistake one makes when one forgets that other people are agents too. When all you can observe is your own mind, and the internal causes from your side which contribute to something in the outside world, it can be easy to forget to consider the other brains contributing to it. So, again, I'm not sure I would really put it down to something as precise as 'assuming one's mind is different from that of other people'.

(Edit: The top comment in this post by Yvain seems to expand a little on what you're talking about.)