Based on: Reaney, P H, (ed. Wilson, R M), 1997, Oxford Dictionary of English Surnames, 3rd ed., OUP, Oxford, unless otherwise stated.

Oakley
Earliest in Andrew’s Kindred: William Oakley, born about 1816, Pontesbury, Shropshire.
From a place named Oakley, or variants, or Oakle Street, Gloucestershire, or Oakleigh, Kent, or Ockley, Surrey.
I am not aware of any connection to Oakle Street.
Onion / Onions
Earliest in Andrew’s Kindred: Edward Onion, father of Thomas Onion, born about 1781, Brewood, Staffordshire.
Old French Oignon, onion seller.
Orgill
Earliest in Andrew’s Kindred: Elizabeth Orgill, born about 1804, Measham, Derbyshire.
Old French Orgueil, pride.
Orton
Earliest in Andrew’s Kindred: William Orton, born about 1776, Clifton Campville, Staffordshire.
From one of many places named Orton, Worton or Overton.

Owen
Earliest in Andrew’s Kindred: William Owen, born about 1700, Brinklow, Warwickshire.
Old Welsh Oue(i)n, Ewan.