This is your sister speaking RE: grey couch. I think if your chairs were a solid bubblegum pink like these, the grey would be very pretty, but since yours (spoiler alert, dear readers) are a luscious poppy pink (or rich girl red as I've dubbed them) with a multi-colored floral fabric, I still vote for a navy couch. BUT, I could be persuaded to go for certain shades and fabrics of grey. Just call me devil's advocate - among other things, I'm sure!
Love the pink chairs! So fun and sassy!