All of the MK5/6/7 brake parts are bolt-on to each other as a compete set, however most do not share the same parts between the sub models.
For instance, an MK5 R32 rear carrier wouldn't be compatible with an MK6/7 rear caliper, however they both turn a 310x22mm rotor. Same for the GTI PP MK7 rear caliper, same operation, however is would not be compatible with a MK5 carrier or TTRS carrier etc.
Bottom line is all of the brake systems bolt on to all or most of the mainstream VW/Audi Platforms.
A TTRS front and rear brake setup will bolt on to any MK5/6/7 provided it's a complete setup of the same origin. An MK6 R setup will fit an MK5, with a full swap, just remember the bracketry and such is not always interchangeable between all of the different 310x22 versions.
The front are easy, they fit! Just be sure he gives you lines and brackets.