So I did some reading and I can't seem to find the relevant information anywhere. I'm probably just missing it.
What action is it to harbor a phantom?
Are there any positional requirements? Ie, touching, within 30ft, within sight, on the same plane, etc.
Does any of this change for a phantom blade spiritualist in relation to his phantom weapon?
The phantom stays fully manifested until it is either returned to the spiritualist’s consciousness (a standard action) ...
There are no other restrictions in respect of distance or LoS/LoE.
You can't harbour your phantom blade. You don't have either the phantom ability or the shared conciousness ability.