The most difficult question maybe: Are you -and Yogananda itself- mixed up in the illusions of the afterlife (astral world)?. I ask, because a friend of mine claims to have Yogananda as "ghostleader". She is not lying. She can’t say whether he is the real Yog. or an astral imitation! I would love to hear, what you think or "know" about this astral world. To me, it looks like there is a danger for the godseeker to get trapped in the "light and love" imitations of the "other side". Thnk u devotee!
Paramhansa Yogananda wrote an entire chapter about the astral world in his autobiography, so you can find out there what he said about it.
He also said that after physical death the spiritual seeker goes to very beautiful realms in the astral world, so beautiful that there is very little incentive to grow spiritually. Truly dedicated seekers, therefore, wish to reincarnate quickly, back on the material plane, in order to be able to work out their material karma sooner. Otherwise, we can waste a huge amount of time in the astral world, enjoying its beauty and ease, but not growing closer to God. The true devotee will be satisfied with nothing less than union with God, and will wish to hasten that experience.
As for the "ghostleader" idea, I don’t even know what that means. Many people claim that Yoganandaji has appeared to them in vision. No doubt some of them are true visions, and that could be happening with your friend. Or as you say, it could be an astral impostor. Or it could simply be your friend’s imagination. It’s not possible for me to say, but she herself can judge by the fruits of it: Is her spiritual growth accelerating because of it, or not? If it is a true vision, then such acceleration will surely happen.
In any event, neither facts nor opinions about the astral world are relevant to our spiritual growth while we live in this physical world. What matters is how we live our lives in the here and now, and whether we are cultivating an ever-deeper, ever-more-loving relationship with God.
Blessings on your quest,