As opposed to surviving with only a slight limp and blood from wounds that stopped bleeding almost immediately

Honestly yes. But if you are correct you will know pretty soon.

And that is why it is so unlikely. Anyone who has any flying experience will know. If you miss an international flight it is very much recorded. This has been the case since lockerbee sp? And more stringent since 911.

Crash investigators will know within hours exactly who did or did not board the flight. And will announce it in a few days once they have made reasonable attempts to contact the families. So if he is faking. The newspapers will know soon.

Adding that to he had family on the flight. And is not seriously injured. Most of the blood on his cloths can come from rubbing scratches. So yes fast healing to the point you cannot tell. Very possible within an hour or 2.

There are unconfirmed rummers saying he opened jumped from the loading door just before the aircraft hit.

Not only is this very possible. But given the closed doors are structural on such aircraft. And would have remained open during the crash. Will show up notably in the investigation. So again will likely be confirmed in days.

Delays will come because while this is an India investigation. The UK and maybe other nations will be keen to help with the investigation. So some negotiating and sharing of expertise will happen.