How were the Abominable Bride murders committed?

Question

If I understand The Abominable Bride correctly (admittedly a very big "if"), the graveyard scene serves to prove to Sherlock that

he's being ridiculous, of course Moriarty is dead, and whatever is happening now has been scheduled since long before his death.

However, if the Ricoletti case really had occurred, then the revelation of

"Ricolleti didn't come back from the dead. Moriarty didn't come back from the dead. People don't come back from the dead, period."

leaves that case unsolved. So, how were the Abominable Bride murders committed?

Answer 1

The solution is available as part of my answer to another question, in which I quote Marion Stein's explanation over at Happy Nice Time People:

Sherlock works it out. Mrs. Riccoletti was dying of tuberculosis. She went on a suicide mission. First, she faked her death by appearing to shoot herself in the head, but she really shot one of her guns at the ground while a co-conspirator splashed blood on the back of her head. A substitute corpse was taken to the morgue. Later, the real Mrs. R killed her husband, and then shot herself. Her body replaced the substitute.