Whisper white is so very barely warm, I think it would achieve what you are after as it is often used in cool colour schemes. You can view the full range of Dulux whites on the attached link. If you click on a colour it will give you the break down of red, green, blue content for each colour. Just remember the colours on the screen will look different on your walls as the computer uses subtractive colour and you'll be painting with additive colour. http://www.dulux.com.au/specifier/colour/colour-atlas

That’s a good idea, we’re going to go with painter on the first room, once he leaves we can decide whether or not we paint the trims. More work, but playing it safe!

Suggestions from neutral colours: https://www.dulux.com.au/colour/colour-trends/2018/essential Ceiling & walls the same colour is a good choice for square set. There will be subtle hue difference in various lighting situations anyway, which provides depth and makes for an interesting look.

Do you have any photos of your area