I know what Frank O’ Connor stated “No purple”, most likely referring to no Covenant.
However, I’ve come up with a theory that there will be Covies. Why? The Forerunner planet may as well have existed since the Precursor era. Maybe there are Covenant who went off the radar, they lost communication to society and have since been isolated since The Great War. Not having any knowledge that the war is over, the Covenant were left to survive with each other. Maybe even gone homicidal… losing all sanity.
That is complete BS, I’m sorry, but that’s just crappy storytelling. So essentially what you’re saying is, the Covenant somehow get lost and conveniently end up on the planet Chief is going towards? All that would show is how uncreative 3 Industries is in crating a new adversary or obstacle to combat the Chief.