Are the mentioned cases considered obsessive whispering, and what should someone who has obsessive doubts about purity do?

The whisperings that have greatly affected you—what we advise you to do is to turn away from these whisperings. Do not pay attention to any of them, for indulging in them leads to great evil and corrupts a person's religion and worldly life.

So, when you perform ablution, do not exceed three washes for any limb. And know that wiping the ears is a Sunnah (definition) according to the majority of scholars, so ablution is not invalidated by omitting it. Also, merely touching the private parts does not necessitate purifying the hand, unless it is confirmed that some impurity has reached it. So, abandon these whisperings and do not concern yourself with them, until Allah Almighty cures you of this affliction.