ZS is BL quality. Even if you can't carry him during the regular season, he's a good roster expansion/playoff guy. Once he's out of options, send him thru revocable waivers every year. Call him up if he clears(you'll be able to demote him), leave him down if he doesn't.
AP is sort of an emergency pitcher. Worth keeping on your 40, probably not worth a full BL roster spot.
PV is the same as AP.
KF, AP, PV, same usage.