Red couches with a gray wall?

I think it would be fine. But go a little deeper with the gray to balance the red. The light gray will look washed out with the intensity of the red. Consider Sherwin Williams 7017 Dorian Gray - it doesn't have the unexpected green or brown undertones that many grays have. Your cabinets & countertop will look fine with gray - it's a neutral as is your cabinets & countertop, & neutrals go with neutrals. You will need an accent color for the red & gray, & a yellow/gold would really look great, perhaps for an adjoining room (kitchen???) I once had a gray kitchen & the dining room was gold, Sherwin Williams 6129 Restrained Gold. It was fabulous. (In fact I'm going back to that color scheme for my next home). Stay within these mid-tones throughout your home & you will be very happy. I really like the SW Fundamentally Neutral palette as those colors work with everything. Go to your local Sherwin Williams store to see what I mean & for any further color guidance. They are very well trained & helpful.