All are PERFECT, Ana. I dig your orange/olive combo, the lace blouse is gorgeous and I love everything about outfit 4.

Great outfits, Ana! #1 and #5 strike me as a bit more creative casual, due to the skirt fabric (it looks like a chino or khaki to me from the photos?); both top halves look appropriately business casual to me though. #2-4 look perfect (LOVE #4). Knit dresses with denim jackets sound good for more casual evening options, and after gauging the dress code you may find that one of the knit dresses is OK for the conference as well (maybe with a little cropped blazer).