Why is the 'Kuf' in "Katzti" small?
Ba'al ha'Turim: Because she foresaw that Esav was destined to destroy the Beis-Hamikdash, which was a hundred Amos tall. 1
Why did Rivka not tell Yitzchak the real reason behind the need to send Ya'akov to Charan?
Rashbam: She acted wisely in giving the reason that she did without telling him that it was on account of Esav's hatred. 1
. Presumably based on the fact that Esav's plans were revealed to her and not to Yitzchak, she realized that Hashem wanted Esav's enmity to be withheld from him until the day he died, despite the fact that he now knew about his Rish'us (Refer to 27:33:2:3 & 4). Moreover, Esav knew why Yitzchak sent Ya'akov to Charan and reacted accordingly. Who knows how he would have reacted had Yitzchak sent Ya'akov away to save him from his (Esav's) hands.