>>8899709
as far as the games go it is rather fast but extended universe states that the prophet's plan to make the jirilhanae the covenant's new useful idiots was put into play way back during harvest, 25 years earlier. more recent events like the heretic uprising and the assassination of regret sped things along.
i'd also venture to guess that the wookiebrutes belong to tartarus' pack exclusively. they're only seen around him, on high charity and the second halo when he lands there.