Karen Ann 2 Piece Identification Help Needed

[Mollzonmarz]

Hi!
I'm so glad this amazing forum exists! Hoping to glean some insight into what the correct details for a pretty incredible 2 piece I've added to my collection recently.
Wanting to find the correct terminology for the over dress piece - what is this thing called?? (Hostess dress, housecoat, beach cover-up, etc.). Also, pretty sure it's 60's, but early, mid, late? Barkcloth?

Thank you all so much!

 

[Midge]

Hmm... I find it hard to make out the details from you photos, so please forgive me if I ask a stupid question... are these shorts underneath? How do they close? And the dress thing - does it button all the way through or only to the waist? Can you show the buttons please? At first look, the print looks newer to me than 60s, but I may be wrong.