Okay, I'm mistaken on point 2, but he is still the only actor to accomplish said fact.
You're not necessarily wrong.
It's not uncommon for a TV show main cast actor/actress to receive onscreen credit for one or more episodes in which they do not appear. imdb lists credited appearances. According to wikipedia, Richard Anderson first appeared on
The Six Million Dollar Man in the second episode. It's also possible that episodes 1 and 2 were originally aired on the same night, and he didn't appear in the first half.
Similarly, Shemp Howard 'appeared' in several
The Three Stooges shorts after his death, replaced by stand-ins, seen from behind. in the movie
Evil Dead, eighteen actors/ actresses are listed in the credits as "fake shemps":