What do the breasts represent?
Rashi #1: They represent Moshe and Aharon, who nurse you.
Rashi #2: They are the Luchos.
Seforno: Afterwards the instructors and teachers (Shofet and Kohen Gadol) were like two harts that fight; they did not agree, like Chazal taught about Pinchas and Yiftach (Bereishis Rabah 60:3).
Malbim (Melitzah): They are the powers of desire and of anger. Both command the power of arousal.
What is the significance of twin harts born to a deer?
Rashi #1: A deer normally gives birth to identical twins.
Rashi #2: The two Luchos had the same measure, and there were five Dibros on each; each Dibur corresponds to the one opposite it. Anochi corresponds to Lo Sirtzach, for a murderer diminishes the Divine image. Lo Yihyeh Lecha corresponds to adultery, for idolatry is like a woman who strays from under her husband to take a foreign man. Lo Sisa corresponds to Lo Signov, for one who steals 1 , in the end he will swear falsely. Zachor corresponds to Lo Sa'aneh, for one who transgresses Shabbos 2 testifies falsely about his Creator, to say that He did not rest on the first Shabbos. Kaved corresponds to coveting, for one who desires [another's wife] will ultimately (have Bi'ah with her, and) father a child who will disgrace him (for he does not realize that he is his father) and honor a man (his mother's husband) who is not his father.
Seforno: Refer to 4:5:1:3.
Malbim (Melitzah): Tzeviyah is an expression of desire. Both desire and anger have one mother. E.g. if one desires another's food, he gets angry at him to take it, and also oppositely 3 .
Sanhedrin 86a: Lo Signov forbids kidnapping, a capital Aveirah, just like the previous Dibur (adultery)! (However, Rashi (Shemos 21:6, citing a Mechilta) says that we pierce the ear of a Nirtza, for it heard Lo Signov, and he stole. - PF)
Even though Zachor is the Aseh to be Mekadesh Shabbos, it was said together with Shamor (Rosh Hashanah 27a). (PF)
I.e. if one is angry at another, he will come to desire what that person has. (PF)
What is the significance of grazing [flocks] in roses?
Rashi: They lead them in a pleasant, straight path.
Seforno: They are among the thorns, in the war against the people of Kena'an.
Malbim (Melitzah): Via grazing among roses, which have a good scent, they will desire and be aroused only for spiritual matters, and Avodas Hashem and His Mitzvos.