"I immediately turned boost pump on and then my engine quit completely."
Hmm, the rule some live by is: If a switch is moved and bad things happen, put it back.
"He says I should not loose power completely if I still have fuel flow and green fuel pressure. To add, I did sump my tank in Toronto and noticed no water in fuel, and fuel cap o ring is fairly new. It was noted the boost pump was functioning properly providing proper pressure with no leaks."
Was the gascolator 'sumped?' A regular fuel cup can be used to sample there and it is the lowest point.
The fuel pressure transducer on J models takes pressure from an output line of the fuel servo. The boost pump pushes through that hose and fitting. The mechanical pump on the engine sucks though that hose. If the B nut was loose it could have been sucking air enough for the engine to not run....but you say you had pressure in the green.
Seems like you must accept the evidence at hand (loose fuel hose).
The firewall fitting bulletin seems to apply to E and F models.