It's hard to give you an accurate quote without having more information. There are a number of factors that come into play when determining your premium and each insurance company may weigh these factors differently when determining what you pay.
Most companies do not consider non-moving violations as a factor when calculating your rate. But every company is different so you may run across one that will rate on non-moving violations, but it is really uncommon.
I can't answer this question - you need to look at the exclusions and special coverages in your renters' insurance policy dec page (declaration page). That part of your policy will specify how much coverage you have - if any.
When you file a claim with your insurance company, the insurance adjuster will determine fault and work with the other parties insurance company to resolve the claim. Usually, the at-fault party would be responsible for the rental coverage.
Since your friend was driving your car for an extended period of time, they would need to be listed as a driver on the policy. If they are not listed on the policy and something happens, the claim can be denied for not listing all drivers of the car.