I have Ryoma and Lyn in teamso. I guess it's theoretically possible to handle 4 Hectors.
4 Takumis may need more setup to make it work though, Ryoma could kill off 2 at most.
4 Linde otoh, is easy for me because Julia just nuke everything blue, which had happened in one of the Arena battle II did where she literally solo'd a team consisting of Marth, Fem Corrin, Nowi, and Robin.