You're right, I overlooked some important slingshot requirements. As for the longevity, I figure the ship can build a facility for growing settlers when it arrives. With no humans on board it can sustain heavier accelerations.
In this setting this was first done when a bunch of immortal vyborgs was on a colony ship, about hundred years from arrival but there was a probe with a matter printer already in the destination. So their got the idea to send the probe both blueprints for a humanoid body printer as well as their mind backups. That got their colony going quite a bit faster but might have resulted in some funny/awkward moments once they met in person later. :)
Presumably you could also run this withou a mind upload and let he individual develop normally.
This is quite nicely described in the engenerator article on Orions Arm (including possible problems): https://www.orionsarm.com/eg-article/4a3d78dc77e6f
In this setting this was first done when a bunch of immortal vyborgs was on a colony ship, about hundred years from arrival but there was a probe with a matter printer already in the destination. So their got the idea to send the probe both blueprints for a humanoid body printer as well as their mind backups. That got their colony going quite a bit faster but might have resulted in some funny/awkward moments once they met in person later. :)
Presumably you could also run this withou a mind upload and let he individual develop normally.