There are several songs where Phil has questioned the lyrics. He does seem a bit self conscious about singing lyrics that don't make sense to him or which he feels sound "silly".
I understand that he disliked singing Firth Of Fifth because he thought "undinal" was a made up word. Abacab doesn't make a whole lot of sense and contains some rather odd lines which is said to be why it didn't make the cut in 2007.
I don't want to get all spoilery but Nic has specifically stated that several of the songs mentioned above as "Phil-centric" are in the set. Though he has also specified that the two most difficult songs that they rehearsed, from the drummer's perspective, haven't made the cut. I am assuming Watcher and Los Endos.
With Mike saying he is adamant the set must be kept to two hours, removing 20-30 minutes of familiar material such as Cage and FoF (if that is the case) might not leave much of a hole for surprises.