As the appearance of the garden has a modernist style with the straight lines and concrete furniture how about a Mondrian influence and add a bold strip of blue? It is a pond and with the right shade it could look really relaxed and contemporary. My daughter's suggestion is a chalky lilac!

Small all in one condo room not sure what color to use for walls after removing wallpaper

I was about to say grey until I read the last line. What about a light brown carpet?

Looking at the bench , I assume that aged look is what you are going for ? How artistic are you ? I'm thinking you'd carry on in a similar vein -- paint the trim in white , but while its still damp ( so within say 30 minutes ) dab on some off-white and even buttery cream , using a sponge , in a bit of a 'rub' pattern . Likewise , I quite like the faded blue jeans look on the sill -- thats a bit harder to do , but maybe a cream base , then thin the blue with turps or water , and also sponge it on , but basically in solid rubs , like you were nuggetting your shoes .