You probably don't need to turn over the soil--probably shouldn't on a steep slope. Talk with your local experts about the best way to convert your paddock. Maybe there are enough native wildflowers growing in there that you could manage by not mowing. Here in the US Midwest we often solarize the soil by covering it with clear plastic sealed all around--this takes a full summer. I have also killed grass by covering it with a tarp for a whole year. For paths I have just laid newspaper, wetted it, and then covered it with mulch. So, it really depends on how big the area is that you are considering. Do find an expert on your area.

A 3x3 shower is too big. Definitely less intimate. I like the second plan! What did you decide to do?

Don't use the wall faucet variety, UNLESS you want to purchase a new top for the vanity. Or return the vanity. Pretty simple. The round hole was meant to have a faucet. Not a "cover" which may also allow water down under, which may also ruin the vanity as there will be no containing water lines beneath the little hole. Bad idea,

Paint your house and ceiling first. You are probably asking for trouble if you put the floors down only to paint over the top of them. If you can, remove the tiles in the kitchen and paint just behind the line of the splashback too. Once painting is done replace kitchen benchtop then splashback. I would call the bathroom its own job and do it individually, unless you only need to paint the ceiling and if a tiler doesn't need to be brought in for anything else in the house? A lot of bathrooms now are getting tiled from floor to the ceiling if this is the case, paint the ceiling first, then tile. If walls need to be painted, it wouldn't really matter if you did them first or last, though if you did it first expect to do some touch-ups. I guess if you really wanted, you could do the first coat before tiles then second after... I don't exactly like stopping and starting painting, so I would do the walls (if they needed to be done) in one hit, after its been tiled. Well that's the order in which I would do everything... Really, for what you're asking, the painting could be done at anytime, but to make life easy on yourself, I would definitely recommend doing it before the floor.