Either Wendy and Chelia will somehow manage Dimaria on their own, which wouldn't be too unbelievable for a shounen series (but people will still be salty just because Wendy is still young), or Gray and Lyon will come to their aid at this point in like the ultimate brother - sister pair team battle Earthland has ever seen. Wendy and Chelia share similar relationships with Gray and Lyon respectively, so... Gray would also be a better match for time magic if that's the case, seeing as... well, Ultear.
There was also still that foreshadowing with Erza and Wendy at the beginning of the war, so it's possible Wendy will get tagged out to help in the harbor itself down the road.
