Since the color is more modern, try to stick to modern furniture. But that color could also be contemporary so you can also use contemporary furniture

Why don't you live in the house for a while and get a feel for things. The curtains are bright but if they are still good quality / newish it would be a very expensive exercise to replace them (I have just spent a few thousand just on three rooms), you can always add a few red cushions or a red toned throw over your existing couch or a rug with a red tones in to it, to tone the red down, if required. Repainting the walls is cheaper than replacing curtains and a piece of art with red tones may also help. As far as furniture is concerned it would depend on what you like style wise. Why not send us a photo after you have moved in. You may find some of your concerns disappear once you are in and settled.

Thank you for your comments. I really appreciate your help. I think we are on the same track. The rugs I have brought home have fought with the terracotta colour plus the busyness of the small tiles. I did come across this picture on Houzz, which I think looks good. What do you think? It would need some of that burnt orange from the chair upholstery as well as the aubergine to tie in but I liked the dark border line, it matched with the grout.

I'd love help picking a couch and rug color for our living room! As much as we would love white, it's a high traffic area with kids so we're leaning toward gray but I'm not sure what color rug would go with that... Also light gray or dark gray? Any help would be appreciated!