Ephraim Skills?

Honestly, that looks great
You could go for pure player phase with mystic boost, if you happen to have it, but there's not much you can do.

Only differend build with aether and close def, but that might not be worth it.

Speaking of, it's not worth the dew to give him the other Sigmund. It might be slightly better, but at least with this one you can buff him up with drives/tactics and he can buff units as well.