civil war era 1860s tintype photo girls, sisters holding flowers - in mourning?

9th plate tintype of two little girls, probably sisters, the youngest holding a small bouquet of flowers. This tintype was originally part of a very small lot of photos that included a post mortem of a boy; based on that, the flowers, dark dresses and their expressions, I am wondering if they were his sisters in mourning. If I had a definite connection to the boy I would've kept them
together...

Behind original mat and glass and in full case. Case has separated covers; image has some age related darkening but is completely visible in person and is otherwise in excellent antique condition.

Shipping: Choice of First Class mailer or boxed Priority Mail.