Abetting
In Canada, Alice would be criminally liable as a party to the offence of murder if she abetted the offence (that includes if she procured or encouraged the offence).
To be a party to the offence as an abettor requires that Alice hold the mens rea for murder. Alice would have to intend, through her encouragement or procurement, for the killing to happen.
See Criminal Code, s. 21(c); R. v. Greyeyes, [1997] 2 S.C.R. 825.
Counselling
Alice would also be criminally liable as a party to the offence if she "counselled" the offence. That is: the "deliberate encouragement or active inducement of the commission of a criminal offence." It requires "nothing less than an accompanying intent or conscious disregard of the substantial and unjustified risk inherent in the counselling."
See Criminal Code, s. 22; R. v. Hamilton, 2005 SCC 47.
Conspiracy to commit murder
Alice would also be criminally liable for conspiracy to commit murder if she and Mark agreed, implicitly or explicitly, on a common unlawful purpose of murder.
See Criminal Code, s. 465(1)(a); R. v. Dery, 2006 SCC 53.
On the facts as described, scenarios 4 and 6 do not assert the required elements for any of the above pathways to criminal liability.
- Scenario 4 has Alice "implying." That does not say that she intended a killing. It does not say the implication was "deliberate." It does not say she was aware of any substantial or unjustified risk in the implication. It does not say that she agreed to killing as a common purpose.
- Scenario 6 says Alice is "joking." That does not say that she intended a killing. That does not say she was aware of any substantial or unjustified risk in the joke. That does not say that she agreed to killing as a common purpose.