As for shoes, no open toe. You may be touring areas where that is not allowed due to safety/biohazard issues. The unbuttoned blazer should be fine.
@blueheeler I am not sure about your comment about matching. do you mean you cannot locate a suit? Or you are looking for separates, but they end up being two different shades of black? I have had that happen often, when I have found a blazer, and it is just a hair off the pants.
It gets frustrating. However, I have had a ton of good luck finding petites (that fit!) at Macy's and JC Pennys. They may be a little more in cost, but the quality has always been there for me. (however, I am not "ultra-petite", so that may be the wrench here)