Pilot Incap just needs to be thorough as far as I'm concerned! Run through the Jeppesens or Aerad ... Being faced by a birdseye of LAX on Finals may be a little daunting to a newbie...
Lay out from the beginning what you expect... if you are training them, tell them what thumbs up, Halt means etc... and stress they must repeat if they don't hear the correct confirmation from you!
One thing I would add... Have had a captain show me here... His exact words were ... If you do find both of us keeled over, put on a headset, presh this button (PTT) and scream for your life... someone will hear you!
I do think basic radio functionality... at least for Senior Crew Members may be of benefit... Yes I appreciate in the event of a Pilot Incap it is a junior crew member that should remain on the deck, but if it's a newbie with a lot of new information in their head, the SCCM is not going to let them suffer. Heck most airlines have 2 seniors on board nowadays anyway... (at least... depends who was on sby that morning! lol)