What is the significance of the extra 'Hei' and 'Vav' in the word "Vatir'eihu"?
Rashi: It implies that she saw that the Shechinah was with the baby. 1
Seforno: She saw that he was a beautiful-looking baby. 2
Why does the Pasuk first refer to him as a Yeled (a little boy) and then as a Na'ar (a youth)?
Ramban #1 (citing the Ibn Ezra): He was physically advanced like an older boy. 3
Ramban #2: Because his forceful cries resembled those of a youth.
Ramban #3 (citing a Midrash): He was a baby, but he behaved like a boy (who did not cry). So Gavriel came and slapped him and made him cry, and Bisyah took pity on him.
Hadar Zekenim: "Na'ar" refers to Aharon, who was there and crying.
See Seforno, who defines the word 'Na'ar' in detail, though it is unclear why it is necessary to do that.
See Ramban's objections. See also Ba'al ha'Turim. See also Ramban, who brings a number of proofs that the Torah does not differentiate between the two words - referring to a youth as 'Yeled' and a baby as 'Na'ar'.
What was it that evoked Bisyah's pity on the baby?
Rashi: Refer to 2:6:2:1.
Ramban #1 (according to the Ibn Ezra) and Seforno: It irked her that such a perfect-looking baby 1 should have been cast into the river.
Ramban #3 2 and Rashbam: Because he was crying.
How did Bisyah know that he was a Jewish baby and not a waif?
Ramban: Because it was only Jews who would hide him there, either to save him or so as not to see him die.
Rashbam: Because he was a boy who was circumcised.
Hadar Zekeni:m Aharon was there and crying and he was [recognizably] an Ivri.
רש"י: את מי ראתה, את הילד: מה גרם לרש"י לפרש כך?
גור אריה: כשכתוב "ותראהו" כבר נזכר הילד ולמה כפל שוב "את הילד"? אלא פרושו "את מי ראתה? את הילד".
רש"י: שראתה עמו שכינה: מנין דרשו זאת?
גור אריה: קשה שהיה צריך לכתוב 'ותראה את הילד' ולא "ותראהו"? אלא "ותראהו" הכוונה לשכינה.
רש"י: קולו כנער: זו דעת רבי יהודה, וקשה מה יענה לטענת רבי נחמיה שא"כ היה משה בעל מום?