Kaga reads as someone not being overly significant in the answer she'll get: If Midou is interested, she'd be thrilled- If not, she can live with it. She's may be a spark, but she's not the bomb, and she's not gonna blow up once she finds out Midou actually likes his bff.
What runs the risk of this going poorly depends entirely on Midou and Hiura. If either of them decides to go all wobbly on the other all of a sudden because of this, then drama might start. (Worst case scenario: Midou tries to repress his feelings by dating a girl. Bad, bad idea, shitty to all involved.) If not though, Midou and Hiura are gonna have to take the step and start admitting that they've caught feelings, either to each other, or a confidant. (I can see Midou coming out to Kaga in the next chapter, raws would suggest that too).
Please, please don't make this overly complicated you two. You have literally everything going for you.