White on trims, doors, ceiling. A lot of good painters still use oil based enamels on doors and architraves. A trick a painter told me years ago was if you paint walls white (or any other colour really) use the same colour but as a ceiling paint on the ceiling. Easier to cut in and can look great rather than using the off the shelf ceiling white that is quite stark and cold. Depends on wall colour, etc. but we used White Watsonia on walls and ceiling and looks fantastic. Normal ceiling white would be too stark in our case.

Not for me, I find the concrete floors too harsh, the one good thing about them when they go off trend easy to cover with something else.

This depends entirely on the amount of light, the purpose of the room, the facing to the sun, and your existing furnishings. You could post few photos to give some guidance but if it is a new build I would suggest heading into a paint store for some sample pots. Once you have the sample pots - paint them onto some old wall paper and move them around and look at them in different lights. If it is for a whole house - think in terms of using half and double strengths to give continuity and some variation. Think about having some walls that could take a deeper tone to add interest to you scheme and also think about your floor coverings. If it is an older home - avoid stark whites and have a hint of your colour in white ceilings as it softens the effect. Generally I suggest avoiding too much yellow or cream and pink hues as these colours tend to date more quickly. Greys, beiges and hints of green are popular - current trends are blue greens and peach tones but will date. I am more familiar with Resene colours and particularly like Thorndon Cream and White Pointer in various strengths . Black White is particularly good for displaying art work and is very popular. You can have these colours put into Dulux paints. Have a search on Houzz to see that tones you like. Good luck.

I'm going to be tricky and recommend staying within the cool palette. Sometimes when you mix warm and cool colours, even if they're neutrals, they can bounce off each other strangely and look bad. Lexicon is pure white with only a touch of black added (no other pigments) and your 'Black White' cupboards may well be the same. Paint some areas with a sample pot first if you're feeling hesitant, but I do think the colour consultant was a great idea. Good luck!