Among the questions I asked the creator of Disa from "Frozen Podcast: Forces of Nature" one of the subjects was about the obsession Anna seemed to have with bringing Disa and Elsa closer together and her answer was… Interesting as the title suggests.
There were a lot of queer people in the group that created the script and the characters for the podcast, and people there when they thought about Disa and Anna had this, as she herself said, inside joke that Anna seemed to want to explore her bisexual curiosity with Disa, that the moment when they went on the roof to look at the stars was like a first informal date between the women.
So, in a way, part of Anna's obsession with wanting to bring Disa and Elsa together, beyond just being that Cupid Syndrome that Anna has in some books of the franchise, could be the desire to bring Disa closer to her and wanting to combine business with pleasure: her sister having a girlfriend, and her having her unresolved passion nearby.
The writers' focus has always been on DElsa since Disa was put into the plot, but Disa's creator confesses that when they talked about fanfic ideas with the other writers in their free time, there were more people excited about DisAnnOff (Disa + Anna + Kristoff) fanfics than fanfics about DElsaMaren (Disa + Elsa + Honeymaren). Disa's creator has always been more DElsa and DElsaMaren.
And to be clear: Disa is a lesbian, so in this DisAnnOff relationship idea it would be the case that Anna has a boyfriend and a girlfriend.
Don't take this too seriously. As I said, quoting the words of Disa's creator, it was more of an inside joke between them than anything else. The subject of the romance between Elsa and Disa was something more serious (after the veto about Honeymaren) that became more and more diluted over time, while this shipp between Anna and Disa was something that would never see the light of day outside of conversations between the writers, but there is this subtext regarding Anna's obsession with the closeness between Elsa and Disa that is ready material for fanfics.
