AMD Essex completed mine for rear section only - you'll need an exhaust company that can weld the join on the rear. You just need the Milltek rear section. It is modular so you don't have to buy the whole cat-back exhaust. You'll find more pictures and details on this forum.
This is the twin GTI style but you can get the single twin pipe exit too.
have you looked at all other Mk7 Golf models to see if any of them have down-turned pipes hidden behind rear valence. My Mk5 GTD had the same too. But Milltek built me the exhaust to match with hidden pipes..I'm sure you'll find a valence
Bumpers cannot be the same as the Estate's is noticeably longer.
Since both hatch and Estate wheelbases are the same, it's the
rear/trunk area what makes the Estate longer.