Hi there! You already have a great envelope for creating the look you want with your white walls, so I would save myself the trouble of painting twice and leave them white.

You can then get these bold, bright colors into your decor through your choice of accessories - rug, pillows, pottery, etc.

Your sofa is the perfect backdrop for some pillows in colors and patterns that convey the Mexican beach house look you are after. Your coffee table looks like it fits this look perfectly. Along with the pillows and rug, you could add an artisanal chair, such as the one in the collage below from Anthropologie. (The rug is also from Anthropologie).

The one good spot I see for a hit of bright wall color is that eating area niche. Showing below Ben Moore Festoon Aqua for this section. You could then add a sideboard, such as the C&B Paloma, to this wall for an organic addition to the bright colors.

The driftwood mirror (Shades Of Light) says "beach house" no matter what country you're in! Perhaps you have a spot in the LR for it?

Hope you get some inspiration from these ideas - I do believe that using bright accessories, rather than bright walls, is the way to go here!