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.

I have a room in both. To be honest I think I bought the Antique White USA in error many years ago. It is a bit too creamy for me. I’d suggest the Natural White but buy an A4 sample from the Dulux site and move it around to see what you think.

Getting professional help would be wise , I think painting all your trims in the garage colour and the porch cover would look beautiful, you can see from this inspiration photo how beautiful the stone looks with the lighter colour, just a few ideas for colour combinations that go with your stone.

The black around your fireplace looks good, I would leave it. The green colour isnt so bad it is just kind of flat and you have no large art pieces on the walls. You could paint or just rearrange what you do have until you renovate. Kmart has the poster frames which are a good size, just rematt existing art or paint your own art to fit that size frame and hang so you get a huge chunk of the white you want without sacrificing the colour he wants or vice versa, get a large piece of mdf and use fabric and make it into art/colour and paint the walls white. You could also do panelling down the bottom in white and keep colour up the top. I am also not a fan of white walls :)