There is a basis, as you have probably read wt commentary and scriptural basis
Yes and it was all very shallow based on literally a few out of context scriptures. Even Jesus' answer to the Sadducees about marriage in the resurrection leaves no doubt. There is "THE" resurrection, not heavenly and earthly. Jesus said there is "one hope", not two. The two flocks that will become one aren't heavenly and earthly, but Jews and all others that get grafted in.
Rom. 6:3, "do you not know that all of us who were baptized into Christ Jesus were baptized into his death?" He says ALL of us. Now verse 5, "If we have become united with him in the likeness of his death, we will CERTAINLY also be united with him in the likeness of his resurrection." In what body was Jesus resurrected?