My parents' old house had a wonderful oak front staircase that my six siblings and I used to race up and down, taking them two or three at a time, with only a casual hold on the railing. I don't know how we managed to never slip or fall. Now, the timber backstairs were steep, and had narrow treads and were poorly lit. We NEVER ran up or down them, but held tightly to the railing and hoped to heck we managed to stay upright. As an adult, my previous home had carpeted stairs, which I slipped on (wearing socks) and fell down twice, though thankfully I was closer to the bottom than the top. My current home has timber stairs with three narrow stainless steel runners stood on edge and inset horizontally across the front of each tread (this is supposed to help reduce risk of slips). I doubt I will get over the anxiety of taking another tumble, so I never go down them wearing socks, and if barefoot, I hold onto the railing for dear life and take it nice and slow. So far so good.

Yes, it does come down to personal taste, but the overall look of your initial kitchen that has the concrete look tiles is beautiful. It would appeal to a wider audience too I think than the navy blue. If you concrete look tiles looked like those in the picture it would look great (as compared to a more matt look concrete tile which may not look as good). I say no to the herringbone look timber in your whole place downstairs. It will probably cost more to lay and I think it adds complexity that you don't need in a home as beautiful as an old queenslander. If you do decide on timber, I would stick with it being just straight planks. (Herringbone is flavour of the month now and I love it for tiles, but it makes a very big statement that not appeal to everyone if you are putting it in a much bigger area like kitchen etc). Good luck.

The black tread would be nice if you were having black flooring everywhere else. I think given you are having matte tallowood everywhere else, it is more streamlined and less 'bitsy' if you stayed all with the one surface.

The cypress pine that you have upstairs is a very distinctive look and I am not familiar with any laminate timber manufacturers doing anything similar in colour and knotiness. This means that you won't find a close match, so I would consider other materials that are completely different. Don't go with a timber-look laminate as it will look really fake compared with the real timber boards that are upstairs. In this photo there are three different flooring materials that are working harmoniously together. There is the clear-stained cypress pine on the lowest level, hardwood treads on the stairs, and slate floor tiles. (If you want to see more photos of this Pettit and Sevitt house then visit: https://secretdesignstudio.com/mr-mrs-modanest-danish-style/ ) Will your ground floor be on a slab, or on stumps? If you are on a slab then consider tiles, polished concrete or carpet. For your stair treads consider polished timber treads. Remember that tiles and polished concrete will last forever if correctly laid, whereas carpet and timber laminate flooring have a limited lifespan as they are much less durable. Best of luck, Dr Retro of Dr Retro House Calls