What does this have to do with criminal law?
Should I sue an individual or individuals who kept starting stuff. The stuff includes many different forms of slander.
"Starting stuff" is not a recognized basis for a civil lawsuit. Slander is. Of course, lots of laypersons are confused about what slander is. However, if someone is slandering you, you certainly may sue. Whether you "should" so obviously involves considerations beyond the merits of the claim (e.g., whether you suffered any damages and whether the potential defendants have the means to pay any judgment you might obtain).
I can not prove all this stuff.
Suing over things you know you cannot prove probably isn't a good idea.
It is hard to prove slander, and at the time the individual was willing to do anything to make the slander look like a lie or was not true.
What this person "was willing to do" isn't relevant to anything. What matters is what he did do. If he slandered you, then proving it shouldn't be a problem. You simply get the persons to who the slander was said to testify.
I strongly suggest you consult with a local attorney.