Why did Rivkah offer to draw water for the camels only after she had finished giving him to drink?
Seforno: Because the Gemara says in Ta'anis (5b) that 'One does not talk during a Se'udah, in case the food enters the wind-pipe instead of the esophagus.' 1
Ohr ha'Chayim: She feared that if she tells him before he finishes, he will rush drinking, amidst concern that she will toil also for the camels.
Akeidas Yitzchak (Bereishis Sha'ar 22): While she was giving him to drink, she thought that if he cannot take for himself to drink, all the more so he cannot draw for his camels.
I.e. perhaps he would answer her while he was drinking. (PF)
Why did she say "I will draw water for the camels", and not "I will give them to drink"?
Hadar Zekenim #1: It is not proper for a woman to feed male animals.
Hadar Zekenim #2: The camels drank from a trough into which she drew water. She needed only to draw it.
Perhaps she wanted to say little, and do much, Refer to 24:44:151:1.
Why does it say "she finished giving him to drink", and not 'he finished drinking'?
Ohr ha'Chayim #1: She brought the jug to his mouth so he would not need to do any toil.
Ohr ha'Chayim #2, Ha'Emek Davar: One who is weary from traveling is prone to drink too much (Ha'Emek Davar