Absolutely feasible. I'd say that's even more reason for proofing by someone with knowledge. Ocean will then know that his red herrings are working.
The thing about knowledge of the script - Ocean has that, but he makes far too many mistakes or clunky grammar, and still has continuity errors. Someone proofing the entire script should be able to do a comprehensive job - if we take Ocean's word that he's written the entire script. I stand by the idea that if it's not comprehensible without insider knowledge, it becomes a barrier for players to comprehend. Secrets and red herrings are fine, they're plot twists but clunky phrasing and grammar aren't red herrings, continuity most likely isn't either, at least 70% of the time. Grammar and lingo - well, that should be consistent through the script. The language side simply requires fluency in the idiom, and seeing where characters slip out of their personality.
At the end of the day, if there is a complete script, someone proofing it should be able to follow without the renders. It needs to make sense. If Ocean relies on visual cues to explain certain things, those should be noted in his draft, otherwise he'll forget his own intention in some cases. Story boards don't need the level of detail to convey emotion, but plot and direction.
If he hasn't completed the script to that level for all the seasons, then proof reading to remove continuity is pointless - the best that can be done is making sure that the loose ends are highlighted for Ocean to verify... but that won't solve the continuity if he gets carried away with expanding sections in later seasons.
Regardless, it completely up to you - I'd just hate doing it myself and tainting my future playthroughs by knowing everything. I'll applaud if you do offer though - Ocean does need the help from an independent view point.