Ugh perish the thought
Literally the stuff of nightmares. Last time that happened I was wearing 4-inch booties, and just barely made it.
I find most flats very comfortable. I guess it depends on the shape of one's feet. My aunt warns me not to wear flats too much though, as they will collapse my arches or something like that. A rubber sole like you describe would be great.
Other than footwear, I'm completely with Petit Lucille above; a loose dress with some stretch is ideal--plus leggings, extra socks and some kind of wrap.
No bra if I can get away with it, or a comfy one.