Whenever I encounter a new metaphysics, my western, scientific upbringing makes me ask, "Of all the ways that existence could be structured, why that way?"
Seriously...an ethereal spirit that flutters from body to body?It's no coincidence that someone else's metaphysical belief system sounds ludicrous. That's because they are all sheer imagination because words or ideas cannot capture the reality that precedes words and concepts. Therefore any metaphysical map is just that--a map, a representation. In that way, it's all fiction.
Granted, some maps are better than others, but why argue over which system is better if they are all simply representational?
To heck with all of them. I'm not saying to give up the practice, just the theories. Give up the concepts.
In Korean Seon (Zen), students ask, "What is this?" until they find the answer. There is no need to speculate. Find the answer. It could take 15-20 years, but at least it's time spent investigating what is here, rather than some pet theory about Storehouse Consciousness or some other theory that is impossible to prove.
Don't waste valuable time squabbling over who has the better interpretation.
Practice until you find the answer.