The attendance requirement is met, if a student is present at least 80%. Therefore, students are allowed to be absent for one teaching unit.
Advanced Microeconomics II is the continuation of Advanced Microeconomics I. It is formally possible to only complete the second course (e.g. for exchange students who need just 4 ECTS), but it would be difficult and doesn't make much sense.
Students should have a good knowledge of introductory microeconomics and game theory, and they should have completed Advanced Microeconomics I. The most important requirement, however, is the willingness to engage with formal (axiomatic) reasoning and proofs.