I love what you've done with your outfits, Alasse. (And I have your same concerns about comfort, with ModCloth... which in my experience is almost synonymous with quality.) I do sense some degree of the '40s and '50s in what you're doing here, particularly with the high-waisted, fuller skirts (but I'm no expert) and some of your blouses, and of course the polka-dot scarf/tie. And wearing longer hair that isn't hyper-straight is more of a retro thing, I think (mine is similar).
I love #3 from both the first and the second sets. The clean, minimalist lines of #3-the-first just speak to me, and I think this combo could be amazing for fall with knee boots that match the belt. I love your cream colored blouse... there's something about the neutral color and the detailing that makes it more to my taste than most bow-style blouses. Can I ask where you found it?
For the second outfit, where you weren't thrilled with the shoes... have you considered a low-heeled pump? I'm thinking about something like this: http://www.6pm.com/fidji-womens-shoes~2. I have a couple pairs of Fidji pumps, and they have a very retro look, but the comfort factor is quite high.
Can I ask you whether the polka-dot accessory is a scarf, or was it intended as a sash? I have gotten great mileage out of "obi" belts, and this looks like a slightly softer and less aggressive take on that style. I would also second Suz's recommendation about the blazers. For wearing with fuller skirts, I gravitate toward shorter/cropped blazers with a full sleeve. I think the full-length sleeve is important for us pears, to avoid too much of a horizontal line near the waist/hips.. the long column of sleeve feels slimming to me. A couple of my favorite jackets actually are cut so that the back is slightly higher than the front, and this helps a lot if you feel like blazers are prone to destroying your waistline with bulk. I think of blazers like jeans... you try on 20 to find the one you love.