[1.] Yes. A criminal acquittal does not exclude a civil suit on the same claims. First, acquittal only addresses the fact that guilt could not be proven beyond a reasonable doubt (requiring, say, a level of confidence> 90%); the standard for civil liability is the preponderance of evidence (which only requires> 50%, or perhaps ≥ 50%, if the harm is easily proven and the onus is then shifted to the defendant to prove self-defense) .
Second, liability could be based on a theory of negligence; the charges against Rittenhouse were based on the theory that he had acted recklessly or intentionally, according to the prosecution. Of course, the negligence investigation made its way into the analysis, as the claim of self-defense depended on whether he reasonably feared death or grievous bodily harm; it would also play a role in any civil action. But at least in principle, there might be more room for allegations of unreasonable behavior in a civil negligence trial than in a case of criminal homicide, attempted homicide or reckless endangerment. (One way this could happen is that the standard for criminal negligence in criminal cases is generally higher than for civil negligence, although in this case the jury instructions did not seem to reflect this.)
This is why, for example, OJ Simpson could lose a civil wrongful death trial even if he had been acquitted in a criminal trial. On the other hand, if someone is sentenced in a trial, with proof beyond a reasonable doubt, which would generally make him or her generally automatically liable in a civil lawsuit based on the same facts and a similar legal theory: If guilt has been proven to a level of confidence> 90 %, this necessarily means it has also been proven at a level> 50%, but not the other way around.
[2.] What about the money? How likely is an 18-year-old to have? Well he was successful in raising money for his criminal defense, and he might be able to raise money for civil defense as well, but I doubt anyone will donate money to him just so the plaintiffs can take him in a lawsuit for damages. (I can’t say if there are any unrestricted contributions from the criminal case fundraising left.)
On the flip side, if Rittenhouse’s parents own a home and have home insurance, it may very well cover a wide range of negligence claims against their minor children (many home insurance policies do), and not only claims resulting from injuries within the home. It is possible that a claim that “Rittenhouse was negligent in shooting me down because his fear that I would kill him or seriously injure him was unreasonable” would be covered by such a policy, although that of course depends on the exact terms of the policy. Such a policy would cover both defense costs and a potential verdict, at least up to the monetary limits of the policy; and that could provide money to settle the case (which of course is the number of cases resolved).
That being said, my feeling about the Rittenhouses’ economic situation (based on a quick glance at media accounts) is that they are probably tenants and probably have no other sources of insurance. responsibility. The main source of such liability coverage is usually home insurance or, for a small percentage of the wealthy population, umbrella policies or similar liability coverage.
[3.] Of course, a jury may well conclude that Rittenhouse was not negligent, even under a preponderance of the standard of proof, in which case he would win the civil lawsuit. (Self-defense is a valid defense in civil cases, although the standard again is the preponderance of evidence.) And, especially if there is no insurance policy available, potential plaintiffs may conclude that it is even pointless to try to continue. But in principle, civil liability following a criminal acquittal is possible.