The lawsuits pose no danger to Vince of eventually going to jail. Civil lawsuits are decided by a preponderance of the evidence, where the person suing only has to convince the judge that his case is 51% likely to be correct. Criminal cases have to be proven beyond a reasonable doubt, which is supposedly 100% surety. Lawsuits themselves hold absolutely no criminal penalties to them. And because civil lawsuits require MUCH less evidence than criminal, a civil judgment rarely is used as evidence in a criminal case because civil judgments are not considered evidence of a crime. So even if Vince loses the civil lawsuit for the concussion lawsuit, it would never result in him being in any danger of going to jail.
According to the IRS, WWE wrestlers are not independent contractors. You're pretty much right on your definition of independent contractor. If the employer controls how and when you do the job, you are an employee and not an independent contractor. Regardless of how much Vince seems to get away with this definition, it is not the correct definition. Here's a very interesting page on that:
Independent Contractor (Self-Employed) or Employee?
Vince is unlikely to sell WWE. In fact, he might simply be saying he is open to it in order to get a rise in stock prices. This sort of talk often has a positive effect on stock price.