(moved to here)
In latest version of Dgraph is mandatory to have a Type Schema https://docs.dgraph.io/query-language/#type-system - So Dgraph is aware of the edges. If you have the Type Schema and add <0x1> <dgraph.type> "Person" . in your data set, you gonna be able to perform expand all queries.
If you need to add the types use this tips in this topic Has some problem when Upgrade Database from 1.0.15 to 1.1.0 - #5 by zhuyaoyhj