בראשית לב:יח פירוש: רש״י, רשב״ם, אור החיים ורד״ק

למי אתה means TO WHOM DO YOU BELONG, implying who has sent thee? The Targum should be דמאן את “of whom are you” and not למאן את as some editions have.

למי אתה, the word עבד is implied, i.e. Esau would ask: “whose servant are you?”

ויצו את הראשון לאמור, He instructed the first one (messenger) to say, etc. The apparently superfluous word לאמו was that even if Esau were not to phrase his enquiry in exactly the words Jacob assumed he would, he would no doubt use words to that effect.