Grey and cream go nicely together so maybe go softer paler shade of house “yellow” (ie warm white perhaps natural white) and perhaps basalt as think gutters are deep ocean and basalt more neutral Grey or ask body corporate what colours are and google matching colours

Thanks ! lovely but would cost a small fortune for a large room.

Loving the vanity and the tapeware. I’d probably use white tiles throughout, but have included one insp pic with a blue tile.

I wouldn't build anything more on top of that. Stability is really important. I'm also wondering about your local rules if you build a new wall, how high does it have to be above the upper patio for safety, what are the rules for balustrades. Sorry, I'm not much help about that aspect, I'm aware of some pertinent questions but not the answers. Especially as they seem to vary in different jurisdictions. I've known of people who had to raise balustrades to meet code when selling, and I've seen listings with no balustrade above a sizeable drop where I've thought how is that legal. You'd really have to find out what your council requires. There should be info on their website I think. If I had the space I'd put in a more gently sloping garden bed, but I come at it from the point of view of someone who always wants more space for plants. :-)