Having mentioned 'Chasanav,' why did the Pasuk add 'Lokechei Benosav'?
Rashi: "Chasanav" refers to his sons-in-law (who lived in Sedom); "Lokechei Benosav," to the Chasanim to whom the two daughters who were still living at home were betrothed.
Targum Onkelus and Targum Yonasan: They are in fact, one and the same - 'his sons-in-law who were married to his daughters.' 1
And the question remains unanswered. According to this explanation, the two daughters who lived with Lot and who accompanied him when he fled Sedom were not necessarily betrothed.
"B'Einei Chasanav" connotes that they could see. The angels blinded everyone!
Moshav Zekenim: They did not really blind everyone. Rather, it was an illusion, so they could not find the house.
QUESTIONS ON RASHI
Rashi writes: "'His sons-in-law' (Chasanav) - [i.e. of] his two married daughters... 'who were to take his daughters' (Lokechei Benosav) - [i.e. to whom] his two daughters at home were betrothed." How do we know to make such a distinction between these two terms?
Gur Aryeh: The word Chasan implies that he had already made a Chasunah (wedding, at Nisu'in). The verse then says Lokechei Benosav, rather than Ba'alei Benosav (the husbands of his daughters); this implies that they were Arusos (betrothed). These must have been 2 sets of sons-in-law.