I would actually try a glossy black, or perhaps a japan black stain with teal scatter cushions over your neutral cushion. Glossy black looks great against blues and green, its a simple classy look and its easy to change it up with scatter cushions should you decide to use it elsewhere in the house.

It may have something to do with the cold, but they do look like they are missing an element, try Epsom salts diluted in a watering can, then in spring either re pot or add a small handful of dolomite lime ( try just one pot first) to make sure it doesn't take them out, definitely reduce your watering so, your potting mix is probably leached of all minerals, do not fertilise until spring

Depends on the installer and what bamboo they're using.

Hi Adelina, As a general rule, MOST porcelain tiles are 10mm thick and glue allowance is 3mm. Have the builder leave 13mm total height in the areas you will be using tiles. See link to some options of neutral coloured porcelain tiles all in the 10mm thickness. https://www.tilecloud.com.au/categories/material/2/Stone%20Look  Assuming the concreting is of good quality, the tiles will be stuck directly to the slab with no need for a screed. (only really required when the concreting is poor or you need to change heights) So that takes care of the downstairs. Bamboo flooring varies anywhere from 6mm all the way up to about 22mm so it really depends on which you choose upstairs. Hope that helps!