Honestly the "quagmire" here is created by dumb laws and/or dumb lawyers.
Mercedes is supposed to have a trademark for automobiles and you're making a video game. That's a different industry so you shouldn't have to license anything from them -- no one is going to be confused into thinking your video game is a motor vehicle and buy it instead of a Mercedes, and that's all trademarks are supposed to be for.
Make it clear that these things don't have to be licensed for video games -- which there is absolutely no sound for them to be -- and you won't have these problems.
Mercedes is supposed to have a trademark for automobiles and you're making a video game. That's a different industry so you shouldn't have to license anything from them -- no one is going to be confused into thinking your video game is a motor vehicle and buy it instead of a Mercedes, and that's all trademarks are supposed to be for.
Make it clear that these things don't have to be licensed for video games -- which there is absolutely no sound for them to be -- and you won't have these problems.