You look wonderful, and cozy! I have the same boots - wore them today, in fact, aren't they comfortable??
I can't advise on the belt, it looks good to my eye. I only know that when I wear skinny belts with cardis like this, because of my shape, the belt ends up slicing off a button. :-( For that reason I tend to like wider belts, they budge less, and worn high - basically ON my rib, not my waist or any soft section prone to expanding. But YMMV.
I absolutely LOVE LOVE LOVE the new zig-zag dress. I saw it when you posted earlier, don't remember whether I weighed in. It's fantastic. The purple dress is great too - but I think you may need to roll the sleeves up a bit higher? Something looks a bit off about the sleeves. Maybe wear them down, or a few inches higher, just above the elbows? The rest of the shape looks fab to me.