One thing I am surprised hasn't been mentioned is a life raft. I have been looking into them and it looks like you can get some pretty compact versions but they are pricey, running about $800+ from what I can tell. To me this seems like the best option for the northeast as the times when I would actually where a survival suit flyfishing are pretty few and far between and putting one on before heading to the water in case of fire or other situation doesn't seem reasonable. Throwing over a throw cushion size life raft able to be depolyed in the water does seem feasible. This also helps protect your passengers as buying a selection of different sized survival suits doesn't fit my budget either. The life raft will be on my list of next items to research and consider buying but not in this season's budget. With most of my runs within 10-15 miles of shore I am counting on quick response times with the GPS enabled PLB.
MOB drills, epi-pens and float plans are great adds. I will admit I have not been that consistent with the float plan even though I know how important they are. I think I have a form in my Power Squadron course book to make some copies of and leave with Patrice before each trip.