A1: They are all need-blind admission for U.S. citizens and permanent residents. This need-blind admission is also true to international students at Harvard, Princeton, Dartmouth and Cornell.
A2: Yale is not in the same boat as Harvard and Princeton because Yale is need-aware admission for international students. However, HPY is 100% of need met internationally, but Cornell is 100% of need met only for US citizens and permanent residents, and this makes Cornell losing student to HPY.
A3: If someone does not consider major, Harvard, along with Princeton and Dartmouth, is the A schools. Cornell is the B school. Yale, along with the other 15 colleges, is the C schools.
4: Yes. Harvard, Princeton, and Dartmouth are the upper Ivies. Cornell is the middle Ivy. Yale, Columbia, UPenn, and Brown are the lower Ivies.