We do need a photo. What colour is the roof?

Very light grey on all walls would be nice or white. Lighter colours like white tend to make spaces bigger and in ur case this needs to be done. The artwork on the weight bearing wall (in kitchen) needs to go as this draws ur eye to the wall . The railings on the stairs need to be painted (either colour of the walls or white)as this will help blend into the background and make the space look bigger.

To be a voice of dissent, have you considered soft greens or green-grey? I've got Baltic Pine floors, pine cabinetry, stainless steel appliances, and black tiles in a BRIGHT west-facing kitchen. I went with Taubmans Swiss Meadow double strength and it compliments all the different elements. If you don't want something "obviously" green, check out Taubmans Alpine Snow (double) - it seems to change colour in different light. It's a pale green in full daylight, but looks soft grey at night.

I like the colours you’ve suggested. I find neutrals restful. Do you have a sample of your cabinetry? An easy way to get a coordinated look, without whites clashing, is to have the white colour matched at the paint shop to the cabinetry. The colour match will tell you if White Beach is on the right track. I’d consider a more plainer white for the trim ie Natural White as suggested above or Berkshire White. For your splashback - could the budget stretch to the benchtop material? If not a tile colour that picks up one of the benchtop fleck colours will give you a coordinated look. Sounds lovely. Come back and post the completed pics.