All fair and good, but the OP specified "benevolent" hauntings, so the whole space (heh!) around ghosts throwing tantrums if not properly appeased is probably a poor fit for the OP's intentions.
I mean in fairness benevolence doesn't mean without fault, someone can be benevolent and unintentionally do harm because of a mistake or simply losing oneself to emotion.
Sticking with the benevolent ghost idea, this seems like a place where the Mexican tradition of Dia de los Muertos and the newly rising cult of Santa Muerte might provide a lot of inspiration. Basically, throw a party for the ghost, acknowledge your own mortality, make light of it with all your friends and promise to help each other out in the afterlife like your deceased friend is doing right now carrying you through space.
I was more thinking like actual "Time-Travel" involved like the
Moberly–Jourdain incident where supposedly they travelled to a muted version of the past and somehow interact with ghostly apparition. While I do believe it is poppycock its not uncommon in old ghost tales like this for protagonists to sometimes go into the past and interact with the world, sometimes even bringing back to the future things as proof or appearing places they weren't before. I remember reading one such story in Suffolk regarding a young girl who claimed she interacted a yellow bricked mansion from the Steward period. Later waking up to mysteriously have the same yellow bricks from the house, which is then confirmed to have existed at least a few hundred years ago.
I think that interesting idea as rather then using FTL maybe their exist powerful enough haunting to these "pasts" or "alternative place" transporting the living around is interesting. If were assuming outside of Ghosts their isn't any super science the concept of FTL is unlikely to happen. Then a possible alternative for this setting is relying on these time-space bending hauntings. With a powerful enough spirit being able to create a time loop of sort to warn the residents of the past or the future, send things back and forth, allow for interaction between different eras.
So say Earth wants to make a colony on say one of Jupiters Moon and so they send out their ships, with nothing set up in advance. However in the future maybe 50 years after the Jovian Colony is established. They are working with their own Ghosts to alter the past and set up an advanced colony for the new settlers. Allowing for a manner of "time traveling" resource like advanced machines that drill out and construct an advanced landing bay and homes for the new settlers. Communicating all the while with Earth governments on how to do this but it very sparky and unreliable sorta like mail it always ends up with something broken inside.
A bit confusing but anything with time travel is.
As an aside what about the corpses of crew member and captain not wanting to abandon their ships, they just keep repeating no matter what their new astronauts do. Every time they try and clean up after the horrible incident that costed half the lives of the SS Normandy, all the dead bodies just keep being found. The Ghosts keep bringing them back because death ain't gonna stop them from leaving their home. So the crews gonna just have to deal with those preserved corpses being on the ship cause getting rid of the entire ship is too expensive and hey it means we have more spiritual works on the station.
Or...
Stuff like making deals with powerful ghosts for some kind of wealth, theirs a few stories revolving around that I've found while reading older English tales. Where a man or woman makes a deal with a strange person who may or may not be the Devil or some powerful Ghost or Fairy... but were focusing on the Ghost. Who offers them a good deal in life even when bad thing come like famine, so their is always enough catch in the fish nets or no one in the family ever gets sick. In turn upon their death bed the entity will get something in return.
Another Or...
What about people who claim they can see "ghosts" like psychics even when they're supposedly invisible to normal people. I would imagine having someone around like that suddenly becomes a requirement for many ships. Like would there be eugenics to keep these bloodlines of ghost seers around? Is it random? Is their some kind of thing you can replicate?
A Third Or... I promise the last one.
What about Ghosts and religion?
How does Ghosts influence all that and religion in turn because all the major religion to some degree have claim over spirits and the whole aspect of the after life. From Pagans to Monotheists that brings up a lot of question and how much roles should religious individual have in space voyages. What happens if say their is a horrible accident on a ship and one ghosts is just really mad at someone and blames them for their death, do they need like a Catholic priests to exocrine the guy or purify him to heaven?
