The whole idea of human external cargo on a longline is just a poor mans hoist.
On that point do you have any idea of the number of SB's and AD's on the existing hoist? Possibly actually a better option.
Many operators use the hoist attachment with a static line - the hoist is painful to keep serviceable.
The only real advantage of a hoist is over water - otherwise.............there is a thing at the top that goes up and down as required - aka a helicopter.