I like Mags and Apoc better honestly, but no they couldn't.
Sinestro could easily take out Magneto (His ring can control electromagnetism as well and he knows every trick in the book - not to mention the other fun stuff he can do), and that leaves Apoc to deal with Black Adam. Apoc is extremely powerful, but he's not THAT powerful.
If nothing else, Sinestro defeats Magneto and then it's Adam and Sinestro vs Apoc. Roflstomp.
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