Surely they jettisoned enough engine parts to lighten the load significantly. Dumping fuel also takes time, creates opportunities for more damage and failure. Swissair MD-11 near Halifax is usually cited as the example in support of landing ASAP even if you wreck a tire or two.
If they took the time to dump fuel from a burning plane with passengers on board, I hope we find out about it for sure. That seems like the wrong choice.