I met with a representative of the Graduate School today. She mentioned that students on the waitlist for the PFL seminars almost always get into the seminar. If you are on the waitlist, you should go to the seminar with the expectation (not the promise) that you'll be able to stay. If registration is required, you must be on the waitlist or registered for the seminar to attend.
Career-oriented seminars are the most relevant to MFM, especially the PDS series and the GLDS series.