Is there really a need? Just follow their guidelines and requirements. Then you will know if your ads are properly placed.
Sure, they have live chat or direct phone number. I'm just not sure how they work with people who don't have established account for long time. I think that they will just direct you to their forum.
Just keep within the guidelines, make some variations and combinations, use channels to see what's the most effective.
Just because it is their code doesn't automatically mean that they will review your placement. Will Clickbank, CJ, ShareASale etc review your placement because it is their code you are using? I have searched all through the AdSense pages and so far I have not seen anything anywhere that indicates that they will review your placement nor have I seen a live chat. Perhaps they will do such a thing, but no one here has provided a url or actual experience.
Negative. Google never made any reviews. I have tried to ask Google to review my ads countless times and Google always told me too find some tips and pointers from their guidelines. Google doesn't want to get involved with AdSense publishers directly.