Is it permissible to lie with good intentions to repel Muslims from people of innovation, such as fabricating stories about them? And is that considered lying or a defense of the Companions and the Mothers of the Believers?

Lying is forbidden and a major sin (kabirah). It is not permissible for a Muslim to resort to it except out of necessity. Defending the noble Companions does not require lying. The Salaf and the scholars of the Ummah defended them through legitimate means, thus making the truth manifest and dispelling falsehood.