I'm embarrassed to say I don't recognize who the girl is. The only girl I'm aware of who has freckles is Ymir, but the hair isn't the right color... If someone could help out, that would be appreciated.
I even doubt this is Connie, his face and height are off, not to mention that Connie wears a white shirt under his jacket uniform, not green.
I think they are that one couple you briefly see in one scene where the girl was desperately trying to CPR the guy's corpse after his body was bitten in half by the Titans. Which would make more sense why the guy is wearing trainee insignia on his jacket.