We're planning to get one of our room walls painted differently!

I could tell you this because I did a course that helped me knowing these colour patterns and stuff!

Also, a sky blue or a purple textured wall can go well with off white or cream colour!

Yes Yes totally get you!

But make sure that you follow this pattern whichever combination you use:

lighter shade on those 3 walls

and a darker contrasting shade on that one different wall

If you'll change this pattern, for ex a darker shade on 3 walls and a lighter shade on one wall then it might end up looking too dark and gloomy inside the room!