Crab,
The main players on the Flight Deck always had wireless comms (through a loop system) in the dark ages (early 70's), and since then more of the deck crew are online for comms. I'll lay a farthing to Threadneedle Street that the guys working on the 53 were on comms to Flyco and to each other.
Why send 5? I don't know, nor do you. I'd take a random guess that the SOP for this has dictated the number, and also that the SOP has been through the food chain both up and down, and nutted out for OH&S.
Why no GE under the machine? No idea, but if there wasn't anything available (as I'd guess, being a ship) then the SOP would have been written accordingly.
We don't know a lot about the background to this (fuel state?) but I think it quite wrong to throw uneducated guesses and turn them into surmised facts, thus judging an evolution as intrinsically wrong. At least, that's what it seems to me that you are doing: but I may well be miss reading your intent, being half a world away and only able to read what I see.
Could be a totally different POV over a decent pint down the pub
(ps apologies for the name calling!)