That story isn't actually canon so much as well-informed fanfiction since Gaider isn't associated with BioWare anymore. We'd therefore prefer not to extrapolate too much from it, especially in terms of the magic it depicts, which seems to expand the bounds of what canon has previously shown to be possible pretty significantly. We'll allow the speaking-to-the-dead spell, but it will need to have been prepared within the last month at the most, and the longer ago it was prepared the less time the spirit will have to communicate and the less coherent it will be, similar to a weak tv signal. We'd also like to make clear that there will be no guarantee that the spirit spoken with is actually the spirit of the deceased, anymore than the Justinia the Herald meets in the Fade is really the Divine. It might be, or it might just be taking a familiar shape and telling your character what they want to hear. Anything else mentioned or depicted in that short story will not be canon in Fade Rift.