1)
What are the connotations of "Yad Chazakah", "Zero'a Netuyah", "Mora Gadol", "Osos" and "Mofsim"?
1.
Hagadah shel Pesach #1: "Yad Chazakah" refers to the plague of Dever (pestilence), "Zero'a Netuyah" to the sword of Makas Bechoros; 1 "Mora Gadol" to the revelation of the Shechinah; 2 "Osos" refers to Moshe's staff with which he performed the miracles, and "Mofsim", to the blood. 3
2.
Hagadah Shel Pesach #2: Each of these five expressions hints at two of the ten plagues.