1)
What are "Olosav"?
1.
Rashi: This is like Ma'alosav (its steps).
2.
Radak, Malbim: Also one who entered Ezras Yisrael via the southern gate, he ascended via seven steps.
2)
What do we learn from "[Echad mi'Po v'Echad mi'Po] El Eilav"?
1.
Rashi: On the top of the Ayil, a date tree was illustrated.
2.
Vilna Gaon: For every Eil in the gate, there was a Timur on each side of it.
3.
Malbim: They were Eilim (like doorposts, on both sides) of the steps.