The front facing camera can easily come out by prying it up with a plastic tool.

The rear facing camera is glued down and needs a little more elbow grease to unstick. If you're lucky, it'll remain sticky and can be reapplied on the new assembly.

TRANSFER PLASTIC SQUARE TO NEW ASSEMBLY

Using tweezers, the plastic square under the rear facing webcam (only) should be peeled up and transferred to the new assembly.

Use a plastic spudger tool to push down the new square if there is enough adhesive left to stick it. If not, use double-sided tape.