Moreover, why did Ulquiorra reach for Orihime?
Ulquiorra started to understand emotions in view of what happened and what he is seeing now. Having compassion for an enemy is not a new concept to Orihime at all. She was feeling the emotional change inside Ulquiorra and she reached out to him, showing compassion and support while he died.
Additionally, does Ulquiorra have emotions? Whether he is consciously aware of this habit or not is unknown. During a speech to Orihime, he claims he does not believe in Human emotions, which he refers to as the "heart," reasoning that if his eye cannot see them, they do not exist.
Similarly, you may ask, does Ulquiorra fall in love with Orihime?
According to Kubo, Ulquiorra did fall in love with Orihime at the end of his life. She may not have "loved" him like she claims to "love" Ichigo, but at least Ulquiorra did mean something to her.
What do each Espada represent?
Starrk is Isolation, Baraggan is Old Age(via Time), Harribel is Sacrifice, Ulquiorra is Emptiness, Nnoitra is Despair, Grimmjow is Destruction, Zommari is Intoxication, Szayelaparro is Madness, Aaroniero is Greed, and Yammy is Rage. As far ideologies go, it's pretty simple to understand.