it seems that girl/girl relationships are tolerated...or not?
Since it's a military setting I would not be surprised about strict "no relationships and displays of affection allowed"-rules and girls having to do it discreetly and out of sight.
Since this series seems to be the concept of "military" as reconceived as "cute girls mostly being sweet to each other," (a notion I am heartily in favor of, btw) I think it's still pretty much an open question at this point.
As I understand it from my brother in the US Marines, in the real world standard military field exercises on hilly terrain generally do not include the instruction, "Take your time and have fun as you advance."
Maybe kissing picnics with senpais constitute a sort of first-year merit-badge ceremony. . .