there was lore that a ghost thought he was about to revive a fallen. So the ghosts themselves lorewise do not know if that is an option. I think there is also lore about how ghosts could revive people to make a guardian who where not their perfect match. I figure it is possible. I have made up a story for a comic i was making durning destiny 1 about how a fallen had saved a ghost from the hive devouring it's light, and had chosen to revive the eliksni for her sacrifice in saving the ghost. She had to develop her own powers and visited places our guardians had traveled and done their deeds, looking to learn what it ment to be a guardian.

Maybe one of the younglings befriends a human boy and dies saving his life, then the traveler sends a ghost to bring him back?

Should be possible. The requirements for resurrection, to our knowledge, are very general and just require you to sacrifice yourself for something you are devoted to.

Traveler left the fallen. They probably won’t get the light as guardians. Cool idea though

I get the feeling we will eventually end up with fallen and cabal light bearers in lore but guardians I think are specifically ones who take actions to protect the city. And the chance of us having them as a playable race is completely unlikely. Would affect crucible and every piece of armor would have to be changed to fit the new races and weapons would have to be scaled to fit cabal.

I think there can be , it's not written anywhere that a Ghost will only choose a Human ,any Eliksni who died fighting for a cause could be chosen(Taniks,The Risen) And Eido is right , Crucible and Gambit are evil, and makes our ghost revive us for fun , what if it decides not to one day ,not to mention Spider is still sending Eliksni to die in Gambit ,that needs to be stopped