1) The hagadah goes through pesukim describing how Hashem heard the prayers and cries of the Jewish people. Vata'al shavasam... Vayishma Elokim... Va' yar es amaleinu. The hagadah brings a derush that this last phrase refers to the drowning of the first born children.
Netziv points out that the time frame of these pesukim is just before Moshe Rabeinu appears on the scene and the chain of events leading to geulah is set in motion. The first born being drowned was a gezeirah that happened 80 years earlier! It would have been just a memory for most people, not a tragedy they were davening about at that moment.
Even if it was just a fading memory for us, says Netziv, Hashem still keeps kavyachol fresh in his mind the tragedy suffered by every Jew. When we cry out in pain, He thinks not just about our current suffering, but He thinks about all we have endured in the past as well.
2) Abarbanel goes through different reasons and approaches to explain why there was a galus in Mitzrayim. The gemara (nedarim 32) already explains that galus is a punishment for some sin committed by Avraham, and the gemara offers three possibilities as to what that sin might have been. Abarbanel in one of his interpretations suggests that the galus was not a gezeirah imposed by Hashem, but was a result of the free will bechira choice of Yosef and his brothers. It was their actions that led to Yosef being sold into Egyptian slavery, which in turn led to Yaakov's decision to go down to Egypt, and the rest is history -- the Egyptians took advantage of the situation and enslaved them.
Abarbanel concludes that this is the gadlus of "v'hi she'amdah." We put ourselves in a bad situation, but Hashem still bailed us out. Our exercise of freedom a will in no way can undermine Jewish destiny.