metamorpho has the ability to . . . hide the vulnerable parts of his mind from telepathic assault. he literally shifts the shape of his brain and protects the vulnerable parts. he can even set a trap for a telepath--a bio-bomb, that sits where his mond 'should' be. it's actually quite a cool ability. 😉
energy beams are easily avoided for an uber shapeshifter. people seem to assume he goes gaseous, but he can easily fight h2h against cl100 guys.
all that said, i'm not sure rex has the offense to take apoc down. he could give him a good run, and he might be able to take a couple, (if he became a partial, invisible gas and got inside apoc he could become iron or lead or propane and simply explode inside apoc's brain . . . not even sure THAT would put apoc down permanently though, but probably) but i think that apoc would outlast him in the end. this is actually a very good match up and the battle would be visually very cool to see.