The study in question answers your #1 directly. Evidence is, they do. So your apples/oranges assertion is bogus.
I think you misunderstood my post. I was agreeing with you. That said, the study does not answer question 1. It answers who gets stopped by police. It does not answer the harder question of who is committing crimes. That's a much harder question to put numbers on because crimes are committed in private and most are not solved. You can use arrest or conviction rates as a proxy for that number; but there are a lot of confounding factors that make arrest and conviction rates by race not much more than a very rough cut at the number.