What is the way to get rid of obsessive thoughts, especially the obsession with disbelief and doubt in creed? And are the common folk among the people of innovation who revile Aisha and the Companions considered disbelievers?

You must seek Allah's help and turn away from whispers (waswas) to cure it. As for the common folk among the people of innovation (Ahl al-Bid'ah), whose shaykhs and leaders are known for their disbelief-inducing beliefs, they are not to be declared disbelievers wholesale merely for belonging to the sect of those innovators. This is unless it is known that some of them hold those disbelief-inducing beliefs and that such a person is not ignorant that this constitutes disbelief. Otherwise, the proof (hujjah) must be established against them. If they persist, then they are to be judged as disbelievers. This matter is to be referred to the people of knowledge. The Permanent Committee was asked about the common folk of some sects known for their disbelief-inducing beliefs, and whether there is a difference between their scholars and their followers. They replied that whoever among the common folk supports an imam of disbelief and misguidance, and champions their masters and leaders out of transgression and enmity, is to be judged by the same ruling as them, whether it be disbelief or wickedness. You are not obligated to research the beliefs of the common folk.