Basic fit is good on all and you're so attractive and dresses are flattering on you so it's hard to say no to any of them. But since we're looking for fab, here's what I see with a close look:
1. Good color on you. Worth repeating. But I would let the dress go. More girly than your persona calls for now, especially the collar. If you still like the sleeves (your call whether or not it's adding too much to the girly effect), a seamstress might be able to remove the collar for you.
2. Though I like the striped dress as a garment, it may be too powerful for your stature, complexion and features. It's not a has-to-go, but I think it's less than fab because it wants to fight you for attention.
3/4. Killer color on you. Agree the bodice doesn't work. If the romance of the neckline cut and sleeves aren't too girly for you and you want to make it work, maybe (?) you could have an inset put in the bodice to bring things up a notch. If I were you I would see if the dress could be made into a skirt, and/or grab a swatch of the fabric and find something fab in that color. You need that color.
5 & 6. I see why you love 5. Practical, versatile, comfortable, nice cut, easy to wear. Looks good on you. I would really want to keep it. And 6 is a killer style on you. My favorite on you in style and cut.
I can't decide on the color, unfortunately. I think this olive is at the least a workable neutral for you though not a glowing color for you like the shades of red and purple in 1 and 3. I would need to see you in person to have a real opinion. It could be a color that's good on you and even better mixed with richer ones. Or it could be one that's just not bad but you could always do better. So hard to tell here.
Go by how you feel in the dress now that you've raised your own issue of color. Do you now feel a bit washed out in it? Or like you want to wear only colors as wonderful on you as the red?
If you're feeling less than 9-10 in either dress color-wise, or ready to be really picky about your truly great colors, either replace them now and plan to repeat the success of these cuts on you in future garments, or wear them as nice/not-bad options while you're continuing to settle into your new sizes.
But if you still feel pretty darn good in these olives when you wear them, then you know it's a good color for you whether or not it photographs well in that light.
Whatever you decide, I think you've hit on some important guiding info about colors, cuts and styles for your evolving self and new sizes. That's always so useful.