It is possible that the reference to the uncircumcised of heart reflects Leviticus 26:41, which speaks of the iniquities of those who are uncircumcised of heart. As circumcision is a sign of the covenant with Jehovah, these would be those who are part of the covenant in flesh—that is, in their circumcision—but not in their heart, or in their spiritual desires.
In line with Jacob’s use of polar opposites, the liar is thrust to hell. The unstated opposite is that truth is God’s domain, and the truthful reside with God.
The reference to the murderer is probably an echo of the commandment that we know as “thou shalt not kill.” The better translation would be “thou shalt not murder,” and Jacob’s discussion is expanding slightly on that theme. It is not the death, but the intent to kill that is prohibited. The literary irony matches one who kills as the one who dies.
Not committing whoredoms would be the same as “thou shalt not commit adultery.” However, there may be some cultural background that is coming into play that has Jacob alter the concept to expand it to something larger than implied in the ten commandments. That will become more important in Jacob’s sermon at the temple, as recorded in the book of Jacob.