Oh lots of good advice. And I appreciate your perspective Bijou.
I suspect it will be standing on a concrete floor and possibly playing games or maybe even doing some flying in an aircraft (hopefully). I will get changed en route but won't have a last minute iron.
I think I am likely to be the dressiest there whatever I wear - which does not bother me - it's more feeling confident and up for whatever goes. So I don't want fussy or low necklines or similar.
The blue floral with sneakers could work, or the purple with sneakers, or the palazzo pants. I think the jumpsuit is now a casual only option.
The others are either too boring (black and rust tunics that I wear all the time to work), I have worn a lot so don't feel special (the shirt dress) or maybe a bit too weekend (white linen and wrap dress).
I will do a try on either tomorrow or Thursday and see what feels right.
Thanks for the advice and feedback - it's good to hear.