I don't know how hot it gets in Auckland in summer (I've only ever been to NZ in winter!) but if it gets hot, then go for a pale colour. Dark roofs should be kept for cold places!

Did you end up painting the ceiling all the same? That's what I would've done!

First of all I would like to say it looks like your parents have brought a lovely looking home. The colouring of the outside of the house it typical for it's age. I would like to suggest that you stick with a light tone for the outside but is the Yellow / Cream isn't working then perhaps consider going for a White with a tiny tint of pale green .... this will blend in nicely with the garden, window joinery and roof but it will not be stark white. Internally I am a bit of a cream on cream kind of a person because I like to add colour through my furnishings, knick-knacks etc but I have to say I did move into a home with a mint green carpet which suits my personality but is not all together practical with pets coming and going and a lounge painted a medium to dark mint and I really love that colour. Originally the hall ways and other room where a butter / cream and just making it a off white really boosted the light and spaciousness of the home. The lounge is still the same minty green and I think I will repaint it a similar colour as it is very relaxing and "natural". So go for something that is restful inside and something clean and almost white outside. Hope that helps.

Whisper White sounds like it'd be great and exactly what you're looking for. What did you end up going with?