Basically, we don't have proof of John's parents, just a few speculations. Nor do we know his birthdate or place of birth.Certainly he was born before 1650.
One of the speculations is from: "John Chapman of Spotsylvania County, Virginia, Thomas Powe of Cheraw, South Carolina and Related Families" Elise Chapman Edmonds, 1971. p. 367:
"Father may be named Thomas or Parents may be named William and Jane"
John Allen is known to have lived early in Lancaster County and later in Middlesex County, but probably didn't move since Middlesex was created from Lancaster.However, he may have also lived in Old Rappahannock, the portion that became Essex.Additional research will determine if he really moved.
Spelling used by early generations may be Allin.There is a 1704 censusin VA with:
Allin Arthur Major Surry County, 1704 Allin Edmd Accomack Allin Erasmus Essex County, 1704 Allin Richard Middlesex County, 1704 Allin Thomas Elizabeth City County, 1704 Allin Thomas King & Queen County, 1704 Allin Widd[o] Henrico County, 1705 Allin Wm. Essex County, 1704