TCO, I think you'll wait a long time to see a list of things that could point to CC's innocence. Very short list:
1) JMM has people who hate her. Ergo, the threats could have been real.
2) Sheri's cousin Enrico Mirabelli once protested The Sopranos for anti-Italian prejudice. Ergo, the Mafia could have done it.
3) Tara Lintz was once married. Ergo, a jealous ex-husband could have done it.
4) Tara Lintz could have done it for crazy Fatal Attraction reasons of her own.
5) Sheri could have been having an affair. A crazy lover could have done it.
6) Some random killer could have done it.
I have a seventh theory: Sheri had the goods on Ron Coleman's empire of embezzlement, aka Grace Church. Ron Coleman brainwashed CC to do it using Evangelical Krav Maga techniques on his mind, and promised Chris the reward of Tara Lintz (you just go git 'er, son).
All but the last have been floated, but none float.