It feels like Edelgard and Thancred probably need to get to know each other more so they can realize their goals sort of line up. Having a sneaky guy around to snoop for info would be a good connect for Edelgard to have.

(As an aside, Goro tried to do a little murder on Himeka back during the PVP event so that's probably not going to endear him to Thancred any)