εὖ γ᾽ εὖ γε ποιήσαντες ὦ Διοσκόρω → well done, well done, you twin Dioscuri!
biassed: P. οὐ κοινός; see biassed.
from interested motives: P. and V. ἐπὶ κέρδεσι.
partly responsible: P. and V. συναίτιος, μεταίτιος (gen.).