吗? Theoretically only the things happened before your application date count. However, getting more prepared makes yourself feel better, right? Also when you could submit more things, and if the IOs happened to take a look at the extra materials to have a better impression on your application, then your efforts would not be wasted, right? Meanwhile, review is indeed a service for the community, which you may want to do later in your career any way.
I don't know about abstracts. The conference papers I reviewed were full papers, and I counted each one of the conference papers, but not just the number of conferences.