Since they do not appear to be erased from their family's history however, any relationship between the two of them would've likely have been a very well kept secret.

I agree with you that we owe it to LGBTQ+ history to be accurate. This photo has been widely circulated online, and because there is almost no information that can be gleamed from this, very different narratives have been suggested for this photo including ones that are narratively bad for LGBTQ+ history. For instance, there is a persistent and completely unfounded rumor tied to this picture that one of the subjects of this picture went mad with love and killed the other.

As far as constructing historical narratives for your cause goes, saying that these two women are in love with each other is definitely on the less egregious side. However, it should probably be considered bad-form to construct narratives based on such scant evidence, as that gives permission for wild claims and speculation.

How many people got the wrong impression about LGBTQ+ history because they thought these two killed eachother? The answer is probably more than zero.