I am not giving credit to the Benz engineers for the twin spark plugs in the 5.7.

As I think can be seen in the above post,
I tried to first give credit to the aircraft hemi's where nearly all of them had twin plugs
.... then I give credit to the Nissan NAPS-Z engineers,
not for inventing twin spark plugs,
but for taking the time and effort to publish emissions data in 'hard numbers' that saved the 5.7 project from naysayers

I certainly think credit is due to 426 designers, and to drag racers who put twin spark plugs back into their engines

As to 'hear-say'
I certainly believe in giving references,
but my memory is not longer good enough to pull them out of the air when the bookmarks in my web browser does not have them.

Do Benz engineers deserve any credit for ANY of the 5.7 design?

I don't know the exact answer,
but again here is some 'hear-say'
... I seem to recall reading that Chrysler contracted out some
CRANKSHAFT
design work to Mercedes Benz on the
4.7 V8
because their German computer models were well thought of for reducing the last bits of tricky torsional vibration,
and also lightening up the rotating weight by putting metal only where its strength was actually needed.

I do not know if any 5.7 crankshaft work was sent out.