Green Arrow isn't typically portrayed as an asshole. He's often a hero with a strong sense of justice, but like any character, he has his flaws and moments of difficult choices.
Yes, it can be. It often gives enough background within the story so that new readers can follow along. They'll quickly get a sense of who Green Arrow is and what he stands for.
After Fan Xian had been shot in " Celebrating Years," he had been saved by Haitang Duoduo and rested for nearly a month under her care. Fan Xian had Haitang Duoduo inform Wu Zhu to come, and Wu Zhu listened to Fan Xian's arrangements and deliberately slowed down his pace, letting the power in the capital automatically split into two factions that supported him and wanted to assassinate him.
Fan Xian was saved by the Qing Emperor after being shot by an arrow in the TV series " Celebrating Years." The Qing Emperor had foreseen the danger Fan Xian might encounter and sent secret guards to save him from the brink of death and return to the Qing Royal Palace. Under the Qing Emperor's concern, Fan Xian rested for nearly a month.
Sure, The Flash and Green Arrow are friends. They share common goals and help each other out on many occasions. Their friendship adds depth to the comic universe.