Are the stats from Zero Beta's passive skills shared with Alpha?
And viceversa. Like for example: "Solid Body: Enhance Beta’s body, permanently increasing her defense and magic defense by 2000, resistance to statuses and elements by 50%, and Stance by 100%. (required level: 110) (max level: 20)"
would work for Aplha and Beta 100% of the time while on tag mode.
Re: Are the stats from Zero Beta's passive skills shared with Alpha?
Not really, only the bonuses that can be shared is their Rapid Time skill, and that's only in Tag Mode.