I think the judge/jury needs to look at the INTENT of the straw purchaser prohibition.
The idea of a straw purchaser is that you are buying a firearm in your name with the intention of giving that firearm to someone who is not eligible to buy the firearm themselves.
For example: a gang member with a felony conviction is a "prohibited gun owner" -- they can't buy a gun legally. So a girlfriend, fellow gang member or family member buys the gun in their name and GIVES the gun to the prohibited person. The actual owner is the prohibited person, not the person who filled out and signed the 4473.
Black didn't do this. He knew Kyle was under age and prohibited from owning the gun. So Black bought the gun in his name and KEPT IT. How Kyle got the gun in Aug 25th is not relevant to the straw purchase charge. The law says Kyle was legally allowed to possess the firearm at age 17 and carry it in public, hence the dismissal of that minor with a firearm charge.
The sticking point is that Kyle gave Black the money. I don't see that coming into play as proof of anything since Black retained possession of the firearm. If Dominick signed the 4473, and he borrowed the money from his mother, would he now be guilty of a straw purchase? The person who pays for the gun is not always the person who signs the 4473, as is often the case of guns purchased as gifts.
I believe this case is going to be dismissed, for the simple reason that Kyle did not have unencumbered possession of the rifle once it was purchased. He borrowed it to go shooting a few times and on the night of the riots, but it was obviously on loan from the owner.
Black and Rittenhouse obviously intended to follow the law and not let the gun be in Rittenhouse's possession as its owner until he was 18. The entirety of the circumstances prove this was not a straw purchase, but rather a way to remain within the boundaries of the law and still have a firearm to use for occasional practice.
If the rifle resided with Rittenhouse at his home instead of at the Black's residence, then that would be a straw purchase. It was not "Kyles rifle" YET!