Hi indianaugust! Welcome to our energetic little wordcrew here! And thanks for the great threads!

Dead ringer is a saying that claims the same story as its tale of origin. But the true source of this can be traced back to horse racing.
Saved by the bell actually is naturally, and very simply, taken from boxing. If a guy was getting hurt, and the round ended, he was "saved by the bell."

Here's an intriguing article by Richard Lederer called Spook Entymologytsuwm, you'll like this one! that explores the origins of each of these (at the bottom of the article) and many others. An enjoyable read.

The "lead-mug and beer" coma that supposedly gave rise to the custom of holding a wake is also debunked there's that word again in lieu of a true linguistic etymology.

http://pw1.netcom.com/~rlederer/arcwdcr2.htm