I wouldn't worry too much about only one EPIRB for the crew (as long as it works) as this is the same situation as most other operators. Not many have individual 406 beacons, although that may change.
Do remember that terminal homing is not carried out on 406 (it only transmits every 50 secs or so) but will still be done on 121.5/243. Can't help you out with the SARSAT question I'm afraid though....