Did the box contain part(s) of the victim? Specifically the heart?
Did the 5 of them do anything to the contents of the box other than look at them?
SwimmingRiddles asks: Was the decision to kill Albert based solely on the discussion with Charlie?
NO
aschrott asks: was Albert aware that Charlie had seen him on the street?
NO
aschrott asks: Did they [Charlie and Albert]talk to one another [on the street]?
NO
Before meeting Albert on the street, did Charlie believe he was dead?
Did the others believe Albert was dead?
Contrawise, would Albert have thought the others were dead before he met Charlie on the street?
Did they think they ate Albert while on the cruise?
SwimmingRiddles asks:
Did the box contain part(s) of the victim?
YOU NEED TO BE MORE SPECIFIC.
SwimmingRiddles asks: Specifically the heart? [I will answer the question, “Did the package contain a heart?”]
NO
SwimmingRiddles asks: Did the 5 of them do anything to the contents of the box other than look at them?
YES. (Albert prepared the box and sent it on. The four of them, however, just looked.)
SingleDad asks: Before meeting Albert on the street, did Charlie believe he [Albert] was dead?
NO
SingleDad asks: Did the others believe Albert was dead?
NO
SingleDad asks: Contrawise, would Albert have thought the others were dead before he met Charlie on the street?
NO
Did Albert eat a specific cut of meat?
If so, was it the brain?
Battles are won in nuance.
Well, I give up, unless Albert ate his own dick and barfed it into the box and send it on, which outgrossed the other four to the extend of homicide.
Besides, I have a subway to catch 
Swimming\Riddles asks: Did they think they ate Albert while on the cruise?
NO
Flypsyde asks: Did Albert eat a specific cut of meat?
YES
Flypsyde asks: If so, was it the brain?
NO
oooh, the brain! There’s a degenerative brain disease that cannibals get. Does it involve that?
damn. Were the others aware they ate human? Did they do it willingly? (this is taking longer than three minutes)
Did the box contain anything other than a written message?
If so, did the box contain a body part of one or more people?
If so, was it one person?
If so, was it a part of Albert? One of Charlie through Edward?
Did he eat the only piece in the box?
SwimmingRiddles asks: oooh, the brain! There’s a degenerative brain disease that cannibals get. Does it involve that?
NO
Coldfire: [eating own genitals and barfing question]
UM… NO.
Did the box contain the head(s) of the victim(s)?
Was Albert a Native of the South Seas?
Were the other four Natives of the South Seas?
Was Albert killed out of disgust for the contents of the box?
Letting my inner child run loose and break things.
Was there any other reason after seeing him, other than the mere presence of a living Albert, that motivated Charlie and the others to kill him?
That’s Kuru. But The Bricker saith that no brains were eaten in the making of this riddle.
Did they (all except Albert) not realize that they were practicing cannibalism at the time?
Was there a photo in the box?
was Albert supposed to have eaten the cut of meat that he did?
was Albert in violation of an agreement made during the cruise?
did something that happened on the cruise separate Albert from the other four (in terms of allegiance)?
were the contents of the package surprising to the other four men?