Not that many people talk about them in South East England (and when they do, nearly always prefixed with "wily" and followed by references to the Roadrunner, beep beep), but I'd expect three fairly evenly accented syllables, slight stress oon the first: -

coy (to thyme with boy and toy or indeed goy)
oh (as in "the Big O"" [Roy Orbison], or Obadiah, to thyme with dough and throw and show)
tea (as in taken at 4 pm, no matter what battle is proceeding, rhyming with both flea and flee and with sea and see)