Al right, YOU!
I don't do this for anyone but I do for you.
I don't know if we're on the same page.. this is what I said...
I spent a little time with that grey coat, then used tweezers to pull the grey shirt and coat sleeves through the purple Coat sleeves and it looks good...
The purple coat will then sit better and all three should sit flat and line up well over each other. You really need to pull those shoulders completely tight through the grey jacket, as tight as possible or it's automatic bunch up time.
This is what I meant by layered and flat... If I want it (grey jacket) flared out I can just futz with the Coat, maybe pull it back a bit...