The red definitely creates a feeling of warmth and is a festive colour. As I live in the southern hemisphere it doesn't feel like Christmas to me. Red sunburnt skin is a Christmas vibe where I am, with the window wide open and hoping for a southerly breeze.
They appear to be waiting in hope of company. It is not necessarily a lonely or sad scene, I think the cat compensates well for companionship, they have a nice comfortable rapport with each other, I think they are accustomed to just being the two of them and are OK with that.
But on this particular evening they appear to be expecting someone special.