The original question had to be edited. I would suggest that one of Abigail's strengths that becomes clear from Act I is that she is strong. Abigail has a will that is able to wrangle the wills of others around her. Abigail possesses a strong interpersonal intelligence throughout the first act. She is able to understand how Parris is acting, and is able to suggest a course of action in which she and he benefit. When she is with the girls, her strength as the leader is evident. Abigail's strength in Act I is the strength that is within her ability to influence others.
Abigail possesses a two- pronged approach in her motivation. The first is that she is looking to escape punishment for her actions in the woods. She does not want to face the punishment from the town elders for what she has done. When Mary Warren suggests that the girls tell the truth and accept the punishment, Abigail repudiates it. A more subterranean motivation that Abigail possesses is that she covets John Proctor. This becomes clear as the Act progresses. The entire reason for her being in the woods was to cast a spell on Goody Proctor so that Abigail could become the next Mrs. Proctor. Abigail craves the affection she once perceived to have with John when they engaged in an affair. In some respects, Proctor is her weakness in that the only time her machinations and scheming seems to take a break is when she is alone with Proctor. Abigail's motivation is not small in any way. She wants Proctor and will do what it takes to get him.
Outside of both of these elements in terms of her strengths and motivations, it becomes clear that Abigail is filled with weakness. Seeing her parents violently killed, being devoid of any remourse or any authentic emotions, and carrying herself in a manner that reflects the world as a means to an end as opposed to an end in its own right are realities that fill Abigail with weakness. The core of her personality, what Proctor would later call a "name," is something that Abigail lacks. Abigail is more concerned with the temporal and the contingent as opposed to anything lasting and permanent. This weakness becomes more pronounced as the drama escalates. She will not stand for anything and thus ends up leaving Salem to reportedly become a prostitute. Abigail's weakness in so far as a condition in which there is only human frailty evident is the projection she offers out of the First Act in the drama.