Greys can be tricky and "read" so very differently in one space to the next, depending on the light. Dulux Raku or Malay Grey may be worth a look for deep tones. Also, check out the colour atlas at the paint store as it will give a lot more choices then the display of sample cards or brochures. This will also tell you the Red, Green and Blue value (RGB). You'll want the blue value to be less then the red to get a warm grey.

It was one of the colours the Dulux rep recommended. If you can, get sample pots and try them out. Best way to check your colours as photos don't always give a true reflection of the colour. Then you can have a look against your tiles and in different light.

Silk would be interesting, not to mention elegant. As for paints, the Silver Illusion appeals, but it might throw green (not sure). I also agree the Tranquil Retreat is a good one. I'm wondering how big the feature wall is, and what is going on this wall, eg TV, fireplace, large artwork, etc.?

Why don't you engage a Dulux Colour consultant to pay you a visit? It is impossible to make sound recommendations from digital photos as there is so much variation with cameras, screens, natural day light and atificial light. There are about 4600 Dulux colours with only about 10% available at your hardware store as colour chips so a Dulux colour consultant can help you find the perfect colour and organise an A4 sized sample. https://www.dulux.com.au/services/colour-design-service/overview?gclid=CjwKCAjw4NrpBRBsEiwAUcLcDGDFlYcONZGEWBc865ndCnsVmwd-CDa84Ise2d5rwdvtwOsVBT_kphoCzVcQAvD_BwE&cid=ppc|google|dulux.com.au_main||||||||||DCDS+-+Brand+%28Australia+Wide%29+-+EM+%28DLX%29|||Brand+-+Colour+Consultant+EM|&ef_id=CjwKCAjw4NrpBRBsEiwAUcLcDGDFlYcONZGEWBc865ndCnsVmwd-CDa84Ise2d5rwdvtwOsVBT_kphoCzVcQAvD_BwE:G:s&s_kwcid=AL!4713!3!335581778534!e!!g!!dulux%20colour%20consultant Best of luck, Dr Retro of Dr Retro House Calls