I'm not sure the concept of the suffering aspect of the Atonement isn't just as figurative as the Garden of Eden account. I don't mean that Christ didn't suffer, because I believe He did, but I mean that the actual transference of the result of sin doesn't have to be literal to make the concept of a vicarious sacrifice a reality. Vicarious suffering doesn't have to be "eye for an eye" suffering, especially in a culture that used scapegoats as a symbol of forgiveness that was highly symbolic. I think it needs to be presented as a literal transference in order to be powerful in the lives of many people who are literalists (just like the Garden of Eden needs to be seen as literal by many people), but I believe the "presentation of the symbolism" and the "actual event" can be different things.
What I mean is that as long as He suffered beyond what any human could suffer, as long as it was deep anguish and emotional/spiritual torment that would drop even the strongest of all to His knees and cause him to beg for it to end (exactly like what Alma described), then that symbolically would qualify as "godly suffering". As long as He was overwhelmed and couldn't continue on His own (needed the additional,angelic strength to get through it), then it would qualify as "a surrogate lamb (the Son) being sacrificed by another (the Father)" symbolically for the sins of the people. Remember, in that culture, just as in ours, in many cases the alternate payment doesn't have to be exactly what is owed; it can be a payment of "everything one possesses" or "one's all". If Jesus gave His all, that "all" symbolically would wipe out the debts of our "all".
There is MUCH of the application of the Plan of Salvation into our mortal existence that can be figurative without losing an ounce of power and "reality" - since symbols are "living" and "real" and "powerful" in every sense of the word.