We're building too this year and our exterior colours are light & dark grey... couldn't afford the timber cladding :( ... and we are having black alum windows, so I say go for black! :) Black windows suit most facades, from the contemporary to the more traditional... Plus what's your alternative, the alum silver? That would look even more blend against the grey exterior colours... whereas black will make the windows a stand out feature of the house... If you're concerned the facade may look a bit drab and if you're game enough, then be bold with a pop of colour in the front entry door... Internally, the black windows (against white/light walls?) will frame the outdoors looking almost like a picture... And no, you are not stuck with a monochrome look inside... you can easily introduce timber (floors, furniture, etc) to create warmth, or any colour you want as black goes with everything... Good luck :)

No, not on the same wall. It is possible to have different colours inside, in different rooms, but outside, each exterior plane should be consistent.

It really depends on what you are happy with and what suits your decorating style./color scheme. Make a mood board of wall colors, furniture, furnishings,lights etc. When you have a clear idea of how you want this space to look, the decision on doors will be easy.

I you are changing from stacker to bi fold doors you should ensure that there is a single door included within one of the bi folds, preferably next to the kitchen. I wonder why you are deciding between white or black windows and doors for this room when you already have white elsewhere. What colour are the internal and external walls.