uh, yeah - you want to go much more casual. Seeing the simple sheath the bridesmaids will be wearing, summer casual will work. Just don't go turquoise.
I wore something similar to this(Lands End) to my SIL wedding in Hawaii a couple of years ago. Although it wasn't cotton knit... it was more of a linen-like fabric. I have this dress in the orange/white pattern and it's like wearing pajamas!
Maybe I should just abandon my notion of a dress and just look for a cute skirt and top instead?
This is a very good plan. I'd stay away from anything with lace overlay. I really like the idea of a summery maxi-dress like Chikabowa mentioned, but if you're super-short (you seem very petite in the pictures) the proportions of those are almost never right.
I wore something similar to this(Lands End) to my SIL wedding in Hawaii a couple of years ago. Although it wasn't cotton knit... it was more of a linen-like fabric. I have this dress in the orange/white pattern and it's like wearing pajamas!