High-definition video footage and imaging will help in distinguishing between target debris and coral debris. As we have seen and, been reliably informed now, it's no picnic down there, no blue lagoon tourist wreck site here. These conditions must influence what we should expect to see. I don't expect to see anything immediately recognisable as aircraft wreckage so, it will be a slow and painstaking exercise to pick out anomolies.
Examples:
Of course engines will be there, maybe in one piece, maybe not but, visible?, buried?, covered in silt? remember, at 1200ft there is 1200ft of erosion above you, heading downwards like a constant rain, landslides won't help either.
Should we expect paint or markings to be visible after 70+ years as well? doubtful if the structure itself couldn't stand up to the conditions what chance paint.
Parts that would be the likeliest to survive?
Plexiglass, a bugger to see though
Larger machined alloy structures, spar, root etc..
Thousands of very small parts scattered around
You have to take into consideration though it will all be scattered about in a debris field, covered in coral, coral residue, silt and so on, not a pretty sight.
Finally as an indicator of the conditions down there they nearly lost the AUV and ROV on numerous occasions and, had to alter the search methods and patterns on a number of occasions to protect them. These 2 machines were under control, any aircraft wreckage down there isn't and, is at the mercy of the elements.
IMHO of course
There's lots to do in the coming months and, time is on their side. Whatever it is isn't going anywhere fast, 70+ years?