Fwiw, I only hit that last one a few days ago. Now my only remaining achievement is the Four Horsemen.
Beating five people at showdown is easy. Play for a while in the 1-2 rings. Except for the all-ins, nobody raises (or if they do, it’s a min-raise), and everyone calls. Don’t bother trying to win chips by betting for value, since it means nothing to your bankroll at this point.