So I replied to his Twitter post about the ice cream and asked if he'd share what he tried that didn't work, in hopes of finding an adaptation that leads to a somewhat more functional pie. :)

Vegan cream cheese and the vegan non-dairy whip options seem to me like the direction to go in, plus agar-agar instead of the gelatin. And if you're making your pie crust, vegan graham crackers plus melted plant-based butter substitute.