This is wonderful! Remember when Sally did a similar dress try-on a few years' back? It's so instructive to see a variety of styles on the same person.
My personal favourite is also the polka dot for its modern retro appeal. But you say it does not fit well? The only place I can notice any potential issue is the back, where there seems to be extra folds of fabric or some pulling. But it is hard to tell whether that's just because of your pose to take the picture. What is the dress made from?
Dress #1 has potential as a very hot weather item if you have a need for such a thing -- depending of course on what it is made from.
I'm the outlier (so far) because I kind of love 7-9. I'm imagining it with a cute low heeled slingback and some dangling earrings. Very Laugh-In mod. I'd wear that dress in a heartbeat! And I think it looks good on you. But it's a real party kind of dress.
I agree that the fit of the floral is lovely but it looks straight on vintage. Which is fine, if that's the look you want, but it seems a bit out of your style wheelhouse. I think you can do better than the last one for the purpose you name.